A shape memory alloy actuator

Abstract

The application discloses a shape memory alloy actuator, comprising: a shell, a first position and a second position are arranged in the shell; a moving piece, which is movably arranged in the shell and moves between the first position and the second position; a first elastic piece, which is arranged in the shell and abuts one side of the moving piece; a second elastic piece, which is arranged in the shell and abuts the other side of the moving piece; the second elastic piece is a shape memory alloy; in the case that the second elastic piece is not affected by temperature, the first elastic piece and the second elastic piece act on the moving piece, so that the moving piece is located at the first position; in the case that the second elastic piece is deformed due to temperature influence, the first elastic piece acts on the moving piece, so that the moving piece moves from the first position to the second position, the second elastic piece is separated from the moving piece, and the second elastic piece is temporarily not affected by temperature. The shape memory alloy actuator has self-protection and self-recovery functions, shape memory alloy damage is avoided, the actuator structure is simple, cost is saved, and the volume is miniaturized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of actuator, and particularly relates to a shape memory alloy actuator. BACKGROUND

[0002] A shape memory alloy (SMA) actuator works by assuming different shapes above or below its transition temperature. This causes the shape memory alloy to undergo a phase change from martensite to austenite, in which the material contracts or lengthens and in the process does work. Typically, a shape memory alloy actuator is caused to be above its transition temperature by means of heating the shape memory alloy. The problem with this approach is overheating (i.e. heating does not stop after the intended transition has occurred in the shape memory alloy material). Overheating causes a longer cooling time, which in some cases can damage the wire. Thus, there is an urgent need for an effective and stable means to prevent overheating of the shape memory alloy material. SUMMARY

[0003] The present application provides a shape memory alloy actuator to solve the technical problem of overheating of the shape memory alloy material.

[0004] To solve the above technical problem, one technical solution adopted by the present application is: a shape memory alloy actuator, comprising: a housing, a first position and a second position are arranged in the housing; a moving part, movably arranged in the housing and moving between the first position and the second position; a first elastic part, arranged in the housing and abutting one side of the moving part; a second elastic part, arranged in the housing and abutting the other side of the moving part; the second elastic part is a shape memory alloy; in the case that the second elastic part is not affected by temperature, the first elastic part and the second elastic part act on the moving part, so that the moving part is located at the first position; in the case that the second elastic part is deformed due to temperature influence, the first elastic part acts on the moving part, so that the moving part moves from the first position to the second position, the second elastic part is separated from the moving part and temporarily stops being affected by temperature.

[0005] According to an embodiment of the present application, the moving part comprises: a moving rod arranged in the first direction; a limiting piece arranged on the moving rod, and the first elastic part and the second elastic part abutting two sides of the limiting piece, respectively.

[0006] According to an embodiment of the present application, a first step surface is arranged in the housing as the first position, and the second elastic part drives the limiting piece to abut the first step surface.

[0007] According to an embodiment of the present application, the housing is provided with a second step surface as the second position, the second step surface is arranged opposite to the first step surface, and the first elastic member drives the limiting sheet to abut against the second step surface.

[0008] According to an embodiment of the present application, two ends of the first elastic member are fixedly connected with the inner wall of the housing and the limiting sheet respectively, and when the first elastic member is elongated to a natural state, the moving member is located at the second position.

[0009] According to an embodiment of the present application, a limiting rope is connected with the inner wall of the housing and the limiting sheet, and when the moving member moves to the second position, the limiting rope is straightened.

[0010] According to an embodiment of the present application, the limiting sheet is a first conductive sheet, and the actuator comprises a second conductive sheet connected to one end of the second elastic member away from the first conductive sheet.

[0011] According to an embodiment of the present application, a third conductive sheet is connected to one end of the first elastic member away from the first conductive sheet.

[0012] According to an embodiment of the present application, the first elastic member is a metal spring, and the first elastic member is sleeved on the moving rod.

[0013] According to an embodiment of the present application, the second elastic member is a shape memory alloy spring, and the second elastic member is sleeved on the moving rod.

[0014] The beneficial effects of the present application are as follows: in the case that the second elastic member is deformed due to temperature influence, the first elastic member acts on the moving member to move the moving member from the first position to the second position, at this time, the second elastic member is still in contact with the moving member and is still in a continuous deformation state of continuing to be influenced by temperature, but since the moving member can only move between the first position and the second position, the second elastic member is separated from the moving member, and the second elastic member immediately suspends the temperature influence, the second elastic member is always within a reasonable temperature influence range, avoiding damage of the second elastic member due to excessive temperature influence. The shape memory alloy actuator of the present application has a self-protection and self-recovery function, avoiding damage of the shape memory alloy, and the actuator of the present application has a simple structure and a small number of components, not only saving cost, but also making the actuator more miniaturized and increasing applicable scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and the other drawings can be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0016] Figure 1 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the first position;

[0017] Figure 2 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the second position;

[0018] Figure 3 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the second position, and the second elastic part is disengaged from the moving part. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of the present application.

[0020] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. Those skilled in the art will understand that the embodiments described herein are merely examples of the present application and are not the only way in which the present application can be practiced.

[0021] Please refer to Figures 1 to 3 , Figure 1 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the first position; Figure 2 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the second position; Figure 3 is a schematic diagram of the overall structure of an embodiment of the shape memory alloy actuator of the present application, in which the moving part is in the second position, and the second elastic part is disengaged from the moving part.

[0022] An embodiment of the present application provides a shape memory alloy actuator 100, as shown in Figures 1 to 3As shown, the actuator 100 includes a housing 110, a moving piece 120, a first elastic piece 130 and a second elastic piece 140. The housing 110 is provided with a first position 111 and a second position 112, and the moving piece 120 is movably arranged in the housing 110 and moves between the first position 111 and the second position 112. The first elastic piece 130 is arranged in the housing 110 and abuts one side of the moving piece 120. The second elastic piece 140 is arranged in the housing 110 and abuts the other side of the moving piece 120, and the second elastic piece 140 is a shape memory alloy. As shown, Figure 1 As shown, in the case that the second elastic piece 140 is not affected by temperature, the first elastic piece 130 and the second elastic piece 140 act on the moving piece 120, so that the moving piece 120 is located at the first position 111. As shown, Figure 2 As shown, in the case that the second elastic piece 140 is deformed due to temperature effect, the first elastic piece 130 acts on the moving piece 120, so that the moving piece 120 moves from the first position 111 to the second position 112, at this time, the second elastic piece 140 is still in contact with the moving piece 120 and is still in a state of continuous deformation due to temperature effect, but since the moving piece 120 can only move between the first position 111 and the second position 112, as shown, Figure 3 As shown, the second elastic piece 140 is separated from the moving piece 120, and the second elastic piece 140 is immediately suspended from the temperature effect. The second elastic piece 140 is always within a reasonable temperature effect range, so as to avoid damage to the second elastic piece 140 due to excessive temperature effect. Moreover, the moving piece 120 moves linearly from the first position 111 to the second position 112 and is kept at the second position 112, so as to output action work. The actuator 100 of the present application can be applied to various structures such as switches.

[0023] It can be understood that after the second elastic piece 140 is separated from the moving piece 120 and suspended from the temperature effect, the second elastic piece 140 can gradually recover the deformation, the second elastic piece 140 is in contact with the moving piece 120 again, at this time, the second elastic piece 140 is deformed again due to temperature effect and is separated from the moving piece 120, and the moving piece 120 is kept at the second position 112. When it is needed to move the moving piece 120 back to the first position 111, the temperature effect on the second elastic piece 140 is only needed to be removed as a whole, under the action of the ambient temperature, the second elastic piece 140 gradually recovers to the initial length, and in the process, the second elastic piece 140 pushes the moving piece 120 to move to the first position 111.

[0024] The shape memory alloy actuator 100 of the present application has a self-protection and self-recovery function, which avoids damage to the shape memory alloy. The actuator 100 of the present application has a simple structure and a small number of components, which not only saves costs but also makes the actuator 100 more compact and increases the applicable scenarios. In some embodiments, the second elastic member 140 is affected by temperature, which means it is heated. The second elastic member 140 deforms when heated, and the moving member 120 moves from the first position 111 to the second position 112. The second elastic member 140 is separated from the moving member 120, and then the heating is temporarily stopped, forming an overheat protection for the second elastic member 140. The second elastic member 140 is heated within a reasonable range to avoid excessive heating and damage. Of course, the second elastic member 140 can also deform when it is cooled, and the moving member 120 moves from the first position 111 to the second position 112. The second elastic member 140 is separated from the moving member 120, and then the cooling is temporarily stopped, forming an overcooling protection for the second elastic member 140. The second elastic member 140 is cooled within a reasonable range to avoid excessive cooling and damage.

[0025] In some embodiments, as shown in Figure 1 The moving member 120 includes a moving rod 121 and a limiting piece 122. The moving rod 121 is arranged in the first direction, and the limiting piece 122 is arranged on the moving rod 121. The first elastic member 130 and the second elastic member 140 abut the two sides of the limiting piece 122, respectively. The first elastic member 130 and the second elastic member 140 drive the movement of the moving rod 121 by applying force to the limiting piece 122.

[0026] The length of the moving rod 121 has various setting forms. The two ends of the moving rod 121 in the first direction include a first end close to the first position 111 and a second end opposite to the first end. At least one end of the moving rod 121 can protrude out of the housing 110. For example, when the moving rod 121 moves to the first position 111, the first end protrudes out of the housing 110. When the moving rod 121 moves to the second position 112, the first end retracts into the housing 110, thereby outputting the action work to the outside of the housing 110 by the first end. For example, when the moving rod 121 moves to the first position 111, the second end retracts into the housing 110. When the moving rod 121 moves to the second position 112, the second end protrudes out of the housing 110, thereby outputting the action work to the outside of the housing 110 by the second end. Of course, both ends of the moving rod 121 can protrude out of the housing 110. When the moving rod 121 moves between the first position 111 and the second position 112, the lengths of the first end and the second end protruding out of the housing 110 change, thereby outputting the action work to the outside of the housing 110. The specific setting form of the moving rod 121 can be adjusted according to the actual application scenario. Of course, in some application scenarios, both ends of the moving rod 121 can not protrude out of the housing 110 to output work inside the housing 110.

[0027] In some embodiments, as shown inFigure 1 As shown, the first elastic member 130 is a metal spring, and the first elastic member 130 is sleeved on the moving rod 121, and one end of the first elastic member 130 can abut or be connected to the inner wall of the shell 110.

[0028] Further, the second elastic member 140 is a shape memory alloy spring, and the second elastic member 140 is sleeved on the moving rod 121, and one end of the second elastic member 140 can abut or be connected to the inside of the shell 110.

[0029] In some embodiments, as Figure 1 When the first step surface 113 is arranged in the shell 110 as the first position 111, in the case that the second elastic member 140 is not affected by temperature, the elastic force of the second elastic member 140 is greater than that of the first elastic member 130, and the second elastic member 140 drives the limiting piece 122 to abut against the first step surface 113.

[0030] Further, as Figure 2 and Figure 3 As shown, the second step surface 114 is arranged in the shell 110 as the second position 112, and the second step surface 114 is arranged opposite to the first step surface 113, in the case that the second elastic member 140 is deformed by temperature, the second elastic member 140 is contracted, the first elastic member 130 acts on the limiting piece 122 and drives the limiting piece 122 to abut against the second step surface 114, at this time, the second elastic member 140 is still in contact with the limiting piece 122 and is still in a state of continuous deformation affected by temperature, but the limiting piece 122 cannot continue to move, and the second elastic member 140 is separated from the limiting piece 122. After the second elastic member 140 is separated from the limiting piece 122 and suspended from being affected by temperature, the second elastic member 140 can gradually recover the deformation, and the second elastic member 140 is in contact with the limiting piece 122 again, at this time, the second elastic member 140 is deformed again by temperature and separated from the limiting piece 122, and the second step surface 114 plays a role of over-temperature protection for the second elastic member 140.

[0031] In some embodiments, the first elastic member 130 is fixedly connected to the limiting piece 122 at one end, and is fixedly connected to the inner wall of the shell 110 at the other end. When the first elastic member 130 is stretched to the natural state, the moving piece 120 is located at the second position 112. In the case that the second elastic member 140 is deformed due to temperature influence, the second elastic member 140 is contracted, the first elastic member 130 acts on the limiting piece 122 and drives the limiting piece 122 to move to the second position 112, at which the second elastic member 140 is still in contact with the limiting piece 122 and is still in the state of continuous deformation due to temperature influence. However, the limiting piece 122 cannot continue to move because the first elastic member 130 does not continue to be stretched, and the second elastic member 140 is separated from the limiting piece 122. After the second elastic member 140 is separated from the limiting piece 122 and the temperature influence is suspended, the second elastic member 140 can gradually recover the deformation, the second elastic member 140 is in contact with the limiting piece 122 again, at which the second elastic member 140 is deformed again due to temperature influence and is separated from the limiting piece 122. The first elastic member 130 plays a role of over-temperature protection for the second elastic member 140.

[0032] In some embodiments, the actuator 100 further comprises a limiting rope (not shown in the figure) connecting the inner wall of the shell 110 and the limiting piece 122, which is straightened when the moving piece 120 moves to the second position 112. In the case that the second elastic member 140 is deformed due to temperature influence, the second elastic member 140 is contracted, the first elastic member 130 acts on the limiting piece 122 and drives the limiting piece 122 to move to the second position 112, at which the second elastic member 140 is still in contact with the limiting piece 122 and is still in the state of continuous deformation due to temperature influence. However, the limiting piece 122 cannot continue to move because the limiting rope is straightened, and the second elastic member 140 is separated from the limiting piece 122. After the second elastic member 140 is separated from the limiting piece 122 and the temperature influence is suspended, the second elastic member 140 can gradually recover the deformation, the second elastic member 140 is in contact with the limiting piece 122 again, at which the second elastic member 140 is deformed again due to temperature influence and is separated from the limiting piece 122. The limiting rope plays a role of over-temperature protection for the second elastic member 140.

[0033] The above lists several ways in which the moving piece 120 cannot continue to move when it moves to the second position 112. In other embodiments, other structures can be used to make the moving piece 120 move at most to the second position 112, so that the second elastic member 140 can be separated from the moving piece 120, thereby playing a role of over-temperature protection for the second elastic member 140 and avoiding damage to the shape memory alloy.

[0034] It is understood that since the second elastic member 140 can avoid being further affected by temperature after being separated from the movable member 120, in some embodiments, the movable member 120 can be the temperature change source of the second elastic member 140. For example, the movable member 120 has a temperature that causes the second elastic member 140 to deform, or the second elastic member 140 is energized when in contact with the movable member 120, thereby generating heat that causes the second elastic member 140 to deform. In other embodiments, after the movable member 120 moves to the second position 112, the second elastic member 140 is separated from the movable member 120, and the second elastic member 140 leaves the heated area, thereby avoiding being further affected by temperature.

[0035] Taking the example of a shape memory alloy that deforms due to heat, and the heat generated by the second elastic member 140 being deformed by electricity when in contact with the moving member 120, the actuator 100 can achieve heating and pausing heating through the following structure:

[0036] like Figures 1 to 3 As shown, the limiting plate 122 is a first conductive plate 170, and the actuator 100 includes a second conductive plate 150, which is connected to the end of the second elastic member 140 away from the first conductive plate 170. When the limiting plate 122 and the second conductive plate 150 are not powered, the second elastic member 140 is not affected by temperature, and the first elastic member 130 and the second elastic member 140 act on the limiting plate 122, causing the limiting plate 122 to be located in the first position 111. When the limiting plate 122 and the second conductive plate 150 are powered, the second elastic member 140 gradually heats up to the transition temperature, the second elastic member 140 gradually contracts, and the first elastic member 130 acts on the limiting plate 122, causing the limiting plate 122 to move from the first position 111 to the second position 112. The second elastic member 140 remains in contact with the limiting plate 122 and continues to deform due to heat until the limiting plate 122 moves to the second position 112. After the second elastic member 140 is separated from the limiting plate 122 and temporarily exposed to the influence of temperature, the second elastic member 140 gradually recovers its deformation and contacts the limiting plate 122 again. At this time, the second elastic member 140 heats up again, deforms, and separates from the limiting plate 122, and the movable member 120 remains in the second position 112. After the limiting plate 122 and the second conductive plate 150 are disconnected from the external circuit, the temperature of the second elastic member 140 gradually decreases under the influence of ambient temperature, and the second elastic member 140 gradually returns to its original length. During this process, the second elastic member 140 pushes the limiting plate 122 to move to the first position 111.

[0037] Furthermore, if Figures 1 to 3As shown, in order to simplify the circuit and avoid the circuit moving to wear, the actuator 100 further comprises a third conductive sheet 160. The third conductive sheet 160 is connected to the end of the first elastic member 130 away from the first conductive sheet 170. The second conductive sheet 150 and the third conductive sheet 160 are respectively connected to two ends of the same circuit, and the current passes through the third conductive sheet 160, the first elastic member 130, the limiting sheet 122, the second elastic member 140 and the second conductive sheet 150. When the third conductive sheet 160 and the second conductive sheet 150 are not powered, the second elastic member 140 is not affected by temperature, and the first elastic member 130 and the second elastic member 140 act on the limiting sheet 122, so that the limiting sheet 122 is located at the first position 111. When the third conductive sheet 160 and the second conductive sheet 150 are powered, the second elastic member 140 gradually heats up to the transition temperature, the second elastic member 140 gradually shrinks, the first elastic member 130 acts on the limiting sheet 122, so that the limiting sheet 122 moves from the first position 111 to the second position 112, and the second elastic member 140 still contacts the limiting sheet 122 and continuously deforms under heat until the limiting sheet 122 moves to the second position 112. The second elastic member 140 is separated from the limiting sheet 122, the circuit is disconnected, and after the second elastic member 140 is affected by temperature, the second elastic member 140 can gradually recover the deformation, the second elastic member 140 contacts the limiting sheet 122 again, at this time the circuit is connected, the second elastic member 140 is deformed again and separated from the limiting sheet 122, and the moving piece 120 remains at the second position 112. When the third conductive sheet 160 and the second conductive sheet 150 are disconnected from the external circuit, the temperature of the second elastic member 140 gradually decreases under the action of the ambient temperature, and the second elastic member 140 gradually recovers to the initial length, and in the process, the second elastic member 140 pushes the limiting sheet 122 to move to the first position 111.

[0038] At this time, the limiting sheet 122 as the first conductive sheet 170 only plays a conductive role and does not need to be directly connected to the power supply. The second conductive sheet 150 and the third conductive sheet 160 are respectively located at the end of the second elastic member 140 and the first elastic member 130, the position is fixed, the circuit structure is simple, and the safety is high.

[0039] The terms "first", "second", "third", etc. in the present application are only used for descriptive purpose and cannot be construed as indicating or implying a quantity of technical features indicated. Thus, the features defined with "first", "second", "third" can include at least one of the features explicitly or implicitly. All directional indications (such as upper, lower, left, right, front, back, etc.) in the present application are only used for explaining the relative position relationship, movement condition, etc. between components, and if the specific posture (as shown in the drawings) changes, the directional indications also change accordingly. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to the process, method, product or device.

[0040] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A shape memory alloy actuator, characterized in that: include: a housing, wherein a first position and a second position are provided in the housing; a moving member, movably disposed on the housing, and moving between the first position and the second position; a first elastic member, disposed in the housing and abutting against one side of the moving member; a second elastic member disposed in the housing and abutting against the other side of the moving member; the second elastic member is made of a shape memory alloy; When the second elastic member is not affected by temperature, the first elastic member and the second elastic member act on the movable member to make the movable member located in the first position; when the second elastic member is deformed due to temperature, the second elastic member contracts, and the first elastic member drives the movable member to move from the first position to the second position, and the second elastic member disengages from the movable member and stops being affected by temperature.

2. The actuator according to claim 1, characterized in that The moving part includes: A movable rod arranged along a first direction; A limiting piece is provided on the moving rod, and the first elastic member and the second elastic member are respectively in contact with two sides of the limiting piece.

3. The actuator according to claim 2, characterized in that A first step surface is provided in the housing as the first position, and the second elastic member drives the limiting piece to abut against the first step surface.

4. The actuator according to claim 3, characterized in that A second step surface is provided in the housing as the second position. The second step surface is arranged opposite to the first step surface. The first elastic member drives the limiting piece to abut against the second step surface.

5. The actuator according to claim 2, wherein: Two ends of the first elastic member are fixedly connected to the inner wall of the shell and the limiting piece respectively. When the first elastic member is extended to a natural state, the moving member is located at the second position.

6. The actuator according to claim 2, wherein: include: A limiting rope connects the inner wall of the shell and the limiting piece, and when the moving part moves to the second position, the limiting rope is straightened.

7. The actuator according to claim 2, characterized in that The limiting piece is a first conductive piece, and the actuator includes: The second conductive sheet is connected to an end of the second elastic member away from the first conductive sheet.

8. The actuator according to claim 7, characterized in that include: The third conductive sheet is connected to an end of the first elastic member away from the first conductive sheet.

9. The actuator according to claim 2, wherein: The first elastic member is a metal spring, and the first elastic member is sleeved on the moving rod.

10. The actuator according to claim 2, wherein: The second elastic member is a shape memory alloy spring, and the second elastic member is sleeved on the moving rod.

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