JP2020172863A - Actuator and tactile sensation application device - Google Patents

Abstract

To provide an actuator capable of obtaining excellent assemblability while attaining measures to cope with fluctuation in a position of an extensible/contractible member.SOLUTION: The present invention relates to an actuator comprising: a long stator 28; a movable element 30 which is disposed while facing the stator 28 in a direction orthogonal to a length direction of the stator 28 and is movable in the orthogonal direction defined as a movable direction; and an extensible/contractible member 32 constituted with a shape memory alloy which is extensible/contractible in accordance with a temperature change, as a material. In the stator 28 and the movable element 30, multiple projections 38 are provided in a staggered manner so as to be arranged side by side in a length direction. The extensible/contractible member 32 is spread over the projections 38 in the stator 28 and the projections in the movable element 30 so as to be alternately suspended therefrom. A groove 60 in which the extensible/contractible member 32 is disposed is formed in the projection 38, and the groove 60 is formed in such a manner that a groove width becomes narrower gradually toward the bottom side thereof.SELECTED DRAWING: Figure 6

Description

The present invention relates to an actuator using a shape memory alloy.

Conventionally, an actuator using a shape memory alloy (SMA) (hereinafter, also referred to as an SMA actuator) is known. It is provided with an elastic member made of a shape memory alloy, and the driving object can be driven by utilizing the expansion and contraction due to the temperature change of the elastic member.

The SMA actuator of Patent Document 1 is provided for each of a long stator, a mover arranged so as to face the stator in a direction orthogonal to the longitudinal direction of the stator, and the stator and the mover. It includes a plurality of convex portions and an elastic member stretched so as to be alternately hung on the plurality of convex portions. The plurality of convex portions are formed with groove portions having a constant groove width in which the elastic member is arranged inside.

Japanese Unexamined Patent Publication No. 2014-88811

As a result of examining the SMA actuator, the present inventor has obtained the recognition that there are the following problems. In the SMA actuator, the position of the telescopic member in the width direction of the stator can fluctuate due to various factors. When this occurs, the output characteristics of the SMA actuator fluctuate. While taking this measure, an SMA actuator that has been devised in terms of assembleability has not yet been proposed, and its improvement is desired.

A certain aspect of the present invention has been made in view of such a problem, and one of the objects thereof is to provide an actuator capable of obtaining good assembling property while taking measures against fluctuations in the position of the telescopic member.

One aspect of the present invention for solving the above-mentioned problems is an actuator. The actuator of this embodiment includes a long stator and a mover that is arranged to face the stator in a direction orthogonal to the longitudinal direction of the stator and can move in the direction orthogonal to the stator. The stator and the mover are provided with a plurality of convex portions alternately in the longitudinal direction, and the elastic member is provided with an elastic member made of a shape memory alloy that can be expanded and contracted by a temperature change. Is stretched so as to be alternately hung on the convex portion of the stator and the convex portion of the mover, and the convex portion is formed with a groove portion in which the telescopic member is arranged inside, and the groove portion is formed. , It is formed so that the groove width becomes narrower toward the bottom side.

According to this aspect, it is possible to provide an actuator capable of obtaining good assembling property while taking measures against fluctuations in the position of the telescopic member.

FIG. 1A is a schematic view showing a state in which the telescopic member is linearly stretched, and FIG. 1B is a schematic view showing a state in which the position of the telescopic member is changed. It is a block diagram of the drive device of 1st Embodiment. It is a side view of the actuator of 1st Embodiment. It is a side sectional view of the actuator of 1st Embodiment. It is a top view of the actuator of 1st Embodiment. It is a cross-sectional view of BB of FIG. FIG. 7A is a view of the stator viewed from the arrow A of FIG. 4, and FIG. 7B is a view of the mover viewed from the arrow C of FIG. 8 (A) is an enlarged view of a part of FIG. 7 (B), and FIG. 8 (B) is a view seen from the arrow D of FIG. 8 (A). It is a perspective view which shows a part of the mover of 1st Embodiment. FIG. 10 (A) is a view of a part of the mover of the first modification from the same viewpoint as that of FIG. 8 (A), and FIG. 10 (B) is a part of the mover of the first embodiment. It is a figure of. It is a figure which saw a part of the actuator of 2nd Embodiment from the same viewpoint as FIG.

The background that led to the idea of the actuator of the present embodiment will be described. See FIG. FIG. 1 is also a schematic view of the stator 28 and the telescopic member 32 viewed from the arrow A in FIG. 4, which will be described later. In this figure, the convex portion 38 of the stator 28 and the mover 30 are omitted.

As described above, the position of the telescopic member 32 in the width direction (Y direction) of the stator 28 may vary due to various factors. Examples of this factor include an impact load applied to the actuator due to a drop of an electric device on which the actuator is mounted, an assembly error that occurs when the actuator is assembled, and the like. FIG. 1A shows an example in which the expansion / contraction member 32 is assumed to be linearly stretched by design. FIG. 1B shows an example in which the telescopic member 32 meanders greatly due to a change in the position of the telescopic member 32 in the width direction Y.

If the position of the telescopic member 32 fluctuates in this way, the output characteristics of the actuator will fluctuate as described above. The output characteristic here means, for example, the acceleration of the drive target driven by the actuator. This acceleration refers to, for example, the difference value (peak peak value) between the maximum value and the minimum value of the acceleration of the drive target when the drive target is simply vibrated by the actuator.

In the present embodiment, it is assumed that an actuator is used as a tactile sensation imparting device that gives a tactile sensation to a user who is touching the driving object by vibrating the driving object. Under such an application, if the acceleration of the drive target driven by the actuator fluctuates, the tactile sensation given to the user touching the drive target changes, and the user may feel dissatisfied. ..

As a countermeasure against fluctuations in the position of the telescopic member 32, it is conceivable to narrow the groove width of the groove formed in the stator or the mover uniformly in the depth direction. However, with this measure, it becomes difficult to insert the telescopic member into the groove of the stator or the mover, which leads to a decrease in the assembleability of the actuator.

Based on this, in the present embodiment, the groove portion is formed so that the groove width becomes narrower toward the bottom side of the groove portion. As a result, it is possible to easily insert the telescopic member into the groove of the stator or the mover while taking measures against fluctuations in the position of the telescopic member, and good assembling property can be obtained. By taking measures against fluctuations in the position of the telescopic member in this way, fluctuations in the output characteristics of the actuator can be suppressed. When an actuator is used for the tactile sensation device as in the present embodiment, the fluctuation of the acceleration of the driving target is suppressed as the output characteristic of the actuator, and thus the change in the usability of the user can be suppressed.

Hereinafter, an example of an embodiment of the present invention made under such a background will be described. The same components are designated by the same reference numerals, and duplicate description will be omitted. In each drawing, for convenience of explanation, some of the components are appropriately omitted, and the dimensions thereof are appropriately enlarged or reduced. The drawings shall be viewed according to the orientation of the symbols. Unless otherwise specified, the terms "contact" and "fixed" in the present specification include not only the case where the two parties directly satisfy the conditions mentioned, but also the case where they are satisfied through other members. The structures and shapes referred to in the present specification include not only those that exactly match the referred shapes but also those that are deviated by an error such as a dimensional error or a manufacturing error.

(First Embodiment)
Refer to FIGS. 2 and 3. The actuator 10 is used in a drive device 12 mounted on a device main body (not shown) of an electric device. The actuator 10 can drive the drive target 14 movably supported by the device body in the drive direction Pa. The electric device of this embodiment is a touch panel device, and the drive target 14 is a touch panel. The drive direction Pa is, for example, an in-plane direction or an out-of-plane direction of the touch panel.

The drive device 12 of the present embodiment is a tactile sensation imparting device. The tactile sensation apparatus can give a tactile sensation to the user U who is touching the drive target 14 by vibrating the drive target 14 by the actuator 10 in conjunction with the touch operation of the user U. In addition to the actuator 10, the drive device 12 mainly includes an urging unit 16, a touch detection unit 18, and a control unit 20.

The urging unit 16 urges the drive target 14 in the opposite drive direction Pb opposite to the drive direction Pa. The urging portion 16 is an elastic body such as a coil spring.

The touch detection unit 18 can detect a touch operation on the drive target 14 by the user U. The touch detection unit 18 is, for example, a capacitive touch sensor incorporated in a touch panel or the like.

The control unit 20 is electrically connected to the expansion / contraction member 32 (described later) of the actuator 10 and the touch detection unit 18. The control unit 20 is composed of a combination of a computer CPU, ROM, RAM, and the like. The detection result of the touch detection unit 18 is input to the control unit 20. The control unit 20 can control the energization of the telescopic member 32.

See FIGS. 3-5. The actuator 10 of the present embodiment mainly includes a stator 28, a mover 30, an expansion / contraction member 32, and a pressing member 34.

The stator 28 is fixed to the device body of the electrical device, and the position with respect to the device body is fixed. The stator 28 has an elongated shape. The mover 30 is arranged to face the stator 28 in the Z direction orthogonal to the longitudinal direction of the stator 28 (hereinafter referred to as the X direction), and can move in the Z direction as the movable direction. The mover 30 has an elongated shape extending along the longitudinal direction (X direction) of the stator 28. The stator 28 and the mover 30 of the present embodiment form an elongated shape that extends linearly.

The stator 28 has a protruding portion 36 that protrudes in the X direction from a portion that faces the mover 30 in the Z direction. The stator 28 of the present embodiment has a pair of protruding portions 36 protruding from the positions facing the mover 30 in the Z direction on both sides in the X direction. The protruding portion 36 is fixed to the main body of the device by using a fixing member such as a screw (not shown).

The outer surface of the mover 30 on one side (upper side in FIG. 3) in the Z direction comes into contact with the drive target 14. As a result, the mover 30 can transmit the movement of the drive direction Pa to the drive target 14 with one side in the Z direction as the drive direction Pa. The drive direction Pa is the direction in which the mover 30 is separated from the stator 28, and the counter-drive direction Pb (the other side in the Z direction) is the direction in which the mover 30 approaches the stator 28. Hereinafter, the direction orthogonal to the X direction and the Z direction is also referred to as a width direction (Y direction).

The stator 28 and the mover 30 are provided with a plurality of convex portions 38, 40 alternately in the X direction at locations facing each other in the Z direction. In the present embodiment, the tip-side portions of the plurality of convex portions 38 and 40 have an arc shape when viewed from the Y direction (viewpoints of FIGS. 3 and 4).

The plurality of convex portions 38 and 40 include a first convex portion 38 provided on the stator 28 and a second convex portion 40 provided on the mover 30. The first convex portion 38 constitutes a part of the first uneven portion 42 provided on the stator 28. The first uneven portion 42 is provided so that the first convex portion 38 and the first concave portion 44 are alternately arranged in the X direction. The second convex portion 40 constitutes a part of the second uneven portion 46 provided on the mover 30. The second uneven portion 46 is provided so that the second convex portion 40 and the second concave portion 48 are alternately arranged in the X direction. The first convex portion 38 is arranged in the second concave portion 48 of the second uneven portion 46, and the second convex portion 40 is arranged in the first concave portion 44 of the first uneven portion 42.

The telescopic member 32 exemplifies a linear wire, but may be a band-shaped belt or the like. The cross-sectional shape of the telescopic member 32 of the present embodiment orthogonal to the axial direction is circular. The stretchable member 32 is made of a shape memory alloy that can be stretchable by changing the temperature. The shape memory alloy of this embodiment is a Ni—Ti alloy. The stretchable member 32 made of a shape memory alloy can be contracted and deformed by reverse transformation (austenite transformation) due to heating, and can be stretched and deformed by martensitic transformation due to cooling.

Both ends of the telescopic member 32 are fixed to the protruding portion 36 of the stator 28 by using a first fixing member 50 such as a screw member. A female screw member 52 is arranged on the side opposite to the mover 30 in the Z direction with the protruding portion 36 of the stator 28 interposed therebetween. A first female screw hole 52a is formed in the female screw member 52. The first fixing member 50 is screwed into the first female screw hole 52a of the female screw member 52, and by sandwiching the elastic member 32 between its own head and the stator 28, the elastic member 32 is made into the stator 28. Fix it. In the present embodiment, the head of the first fixing member 50 presses the expansion / contraction member 32 toward the stator 28 via the washer member 53. At this time, the end portion of the telescopic member 32 is sandwiched between the first fixing member 50 and the stator 28 in a state of being wound around the shaft portion of the first fixing member 50. A plate-shaped electrode member 54 having conductivity is sandwiched between the head of the first fixing member 50 and the stator 28. Both ends of the telescopic member 32 are electrically connected to the control unit 20 via the electrode member 54 and electrical wiring.

The telescopic member 32 is arranged between the stator 28 and the mover 30. The telescopic member 32 is stretched in the X direction so as to alternately hang on the first convex portion 38 of the stator 28 and the second convex portion 40 of the mover 30. The telescopic member 32 is alternately hung on the first convex portion 38 of the stator 28 facing the mover 30 and the second convex portion 40 of the mover 30 facing the stator 28. As a result, the telescopic member 32 can drive the mover 30 together with the drive target 14 in the drive direction Pa by the contraction deformation.

The pressing member 34 is individually provided corresponding to both sides of the stator 28 in the X direction. The pressing member 34 controls the detachment of the mover 30 with respect to the stator 28 in the Z direction by pressing the mover 30 toward the side closer to the stator 28 (lower side in FIG. 4) in the Z direction. The pressing member 34 of the present embodiment is a leaf spring, and presses the mover 30 in a state of being elastically deformed in the Z direction.

The pressing member 34 is fixed to the stator 28 by using a second fixing member 56 such as a screw member. The second fixing member 56 is fixed to the stator 28 by being screwed into the second female screw hole 52b of the female screw member 52.

An example of the operation of the drive device 12 described above will be described. When the predetermined drive start condition is satisfied, the control unit 20 energizes the telescopic member 32 under the predetermined energization condition. The drive start condition of the present embodiment is that the touch operation on the drive target 14 is detected by the touch detection unit 18. The energization condition is set so that the telescopic member 32 can be contracted and deformed by heating the telescopic member 32 to a temperature range equal to or higher than the reverse transformation start temperature. In this way, when the touch operation by the touch detection unit 18 is detected, the control unit 20 can contract and deform the expansion / contraction member 32 by energizing the expansion / contraction member 32.

When the telescopic member 32 contracts and deforms due to the energization by the control unit 20, the mover 30 is driven in the drive direction Pa, and the movement of the mover 30 is transmitted to the drive target 14, so that the drive target 14 is also driven in the drive direction Pa. Driven by. At this time, the drive target 14 is driven in the drive direction Pa against the urging force of the urging unit 16.

When the energization of the telescopic member 32 by the control unit 20 is stopped, the telescopic member 32 is stretched and deformed so as to be restored to its original shape by heat dissipation cooling. Along with this, the transmission of the force from the telescopic member 32 to the driving target 14 is released, and the driving target 14 is pushed back in the counter-driving direction Pb by the urging force of the urging portion 16. The drive device 12 vibrates the drive target 14 by momentarily moving the drive direction Pa and the counterdrive direction Pb. As a result, the vibration of the drive target 14 is transmitted to the user who is touching the drive target 14, and the user is given a tactile sensation.

See FIGS. 4, 6 and 7. Grooves 60 in which the telescopic member 32 is arranged are formed in the convex portions 38 and 40 of the stator 28 and the mover 30. The groove portion 60 regulates the detachment of the telescopic member 32 in the Y direction with respect to the stator 28 and the mover 30. In the present embodiment, the groove 60 is formed in each of the plurality of first convex portions 38 of the stator 28, and the groove portion 60 is formed in each of the plurality of second convex portions 40 of the stator 30. The groove 60 of the first convex portion 38 is formed on the stator 28 at a position facing the stator 30 in the Z direction, and the groove 60 of the second convex portion 40 is formed at a position facing the stator 28 in the Z direction. It is formed on the mover 30. The groove portion 60 is formed so as to be recessed in the Z direction with the Z direction as the depth direction of the groove portion 60. It can also be considered that the groove portion 60 is formed so as to be recessed from the tip portions of the convex portions 38 and 40 toward the proximal end side. The groove portion 60 is formed so as to extend in the X direction with the X direction as the longitudinal direction of the groove portion 60.

The bottom portion 60a of the groove portion 60 of the present embodiment is provided with a flat surface 64 extending in the Y direction in a cross section orthogonal to the X direction. The groove portion 60 has a pair of side surfaces 66 facing each other in the width direction (Y direction) of the groove portion 60. The pair of side surfaces 66 extend from the deepest portion 68 of the groove portion 60 toward the inlet side of the groove portion 60. The deepest portion 68 here means the deepest portion in the depth direction (Z direction) of the groove portion 60 in the cross section orthogonal to the X direction. The deepest portion 68 of the present embodiment is composed of flat surfaces 64 provided at the bottom of the groove portion 60, and side surfaces 66 extend from both ends in the Y direction toward the inlet side of the groove portion 60.

The groove portion 60 is formed so that the groove width becomes narrower toward the bottom side thereof. The groove portion 60 of the present embodiment is formed so that the groove width becomes continuously narrower toward the bottom side in the entire range from the inlet portion 60b to the bottom portion 60a of the groove portion 60. From another point of view, the side surface 66 of the groove portion 60 is provided with a groove width changing surface 70 that continuously narrows the groove width toward the bottom side thereof. The groove width changing surface 70 is provided on the side surface 66 of the groove portion 60 in the entire range from the inlet portion 60b to the bottom portion 60a of the groove portion 60. The groove width changing surface 70 is provided so as to be inclined with respect to the direction axis Ld in the Y direction in a cross section orthogonal to the X direction.

A state in which the shape of the telescopic member 32 has not changed due to an external force other than gravity, that is, a natural state in which an external force other than gravity is not applied to the telescopic member 32 is called an "undeformed state". The groove portion 60 of the present embodiment is set in a shape so that the telescopic member 32 in such an undeformed state can contact the deepest portion 68 of the groove portion 60. In order to realize this, the groove portion 60 of the present embodiment is set to a shape in which the stretchable member 32 in the undeformed state can contact only the deepest portion 68 (flat surface 64) of the groove portion 60. When the telescopic member 32 in the undeformed state comes into contact with the flat surface 64 of the groove 60, it is arranged at a distance from the pair of side surfaces 66 of the groove 60 and does not come into contact with those side surfaces 66. ..

As a result, when the load Fa toward the bottom side of the groove portion 60 acts on the expansion / contraction member 32, the expansion / contraction member 32 can be prevented from biting into the groove portion 60. Such a load Fa acts on the stretchable member 32 when tension is applied to the stretchable member 32 due to shrinkage deformation of the stretchable member 32 or the like. From another point of view, it can be said that the groove portion 60 is set in a shape that prevents the expansion / contraction member 32 from biting into the groove portion 60 when a load along the Z direction acts as such a load Fa.

The cross-sectional shape of the telescopic member 32 of the present embodiment is circular, but a case where the cross-sectional shape is set to, for example, an ellipse as another cross-sectional shape is considered. In this case, when the cross-sectional shape of the telescopic member 32 is rotated around the axis of the telescopic member 32, the conditions in the preceding paragraph may be satisfied at any of the rotation positions.

Among the groove portions 60 formed in the convex portions 38 and 40, the portion having the largest groove width at the inlet portion 60b of the groove portion 60 is referred to as a reference portion. The reference portion in the present embodiment is a portion that passes through the tip Tp of the convex portions 38 and 40. FIG. 6 is also a cross-sectional view passing through the reference point. At this reference point, the groove width at the bottom 60a of the groove 60 is wb, and the groove width at the inlet 60b of the groove 60 is we. At this time, the groove portion 60 of the present embodiment is formed so as to satisfy the condition of the following formula (1).
wb ≤ we × 0.5 ・ ・ ・ (1)

The effect of the actuator 10 described above will be described.

The groove portions 60 of the convex portions 38 and 40 of the present embodiment are formed so that the groove width becomes narrower toward the bottom side thereof. Therefore, in the cross section orthogonal to the X direction, the groove width we at the inlet portion 60b of the groove portion 60 is the same as the groove width wb at the bottom portion 60a of the groove portion 60, and the expansion / contraction member is formed inside the groove portion 60 from the inlet portion 60b. It becomes easy to insert 32. Along with this, good assembleability can be obtained when assembling the actuator 10.

Further, in the cross section orthogonal to the X direction, when the expansion / contraction member 32 is arranged at the bottom of the groove 60, the groove width wb at the bottom 60a of the groove 60 is the same as the groove width we at the inlet 60b. Fluctuations in the position of the telescopic member 32 in the width direction (Y direction) of the stator 28 can be suppressed.

Combined with these, good assembleability can be obtained while taking measures against fluctuations in the position of the telescopic member 32 in the Y direction.

The groove portion 60 is set in a shape so that the stretchable member 32 in the undeformed state can contact the deepest portion 68 of the groove portion 60. Therefore, when the telescopic member 32 tries to move toward the bottom side of the groove 60 due to the tension applied to the telescopic member 32, it is possible to avoid a situation in which the telescopic member 32 bites between the pair of side surfaces 66 of the groove 60. That is, when the expansion / contraction member 32 is arranged inside the bottom portion 60a of the groove portion 60, the situation where the expansion / contraction member 32 bites into the groove portion 60 can be avoided. Therefore, while suppressing the fluctuation of the position of the telescopic member 32 by the bottom portion 60a of the groove portion 60, it is possible to avoid an increase in the sliding resistance when the telescopic member 32 expands and contracts, and the expansion and contraction operation can be smoothed.

Next, other features of the actuator 10 will be described. Let μ [−] be the coefficient of static friction between the side surface 66 of the groove 60 with which the elastic member 32 comes into contact and the elastic member 32. At this time, based on this static friction coefficient μ, the friction angle θ0 [°] can be obtained as the angle with respect to the direction axis Ld in the Y direction from the following equation (2). This friction angle θ0 is the minimum at which an object that comes into contact with the side surface 66 of the groove 60 in a stationary state starts to slide when a load Fa is applied to the bottom side of the groove 60 along the Z direction. It becomes the angle of.
θ0 = arctan (μ) ・ ・ ・ (2)

At this time, in the cross section orthogonal to the X direction, the inclination angle θ1 of the side surface 66 of the groove 60 with respect to the direction axis Ld in the Y direction is set to be larger than the friction angle θ0 determined based on the above-mentioned static friction coefficient μ. The inclination angle θ1 here means an angle formed by a tangent line passing through the side surface 66 of the groove portion 60 and the direction axis Ld in the Y direction in a cross section orthogonal to the X direction. In the present embodiment, the inclination angle θ1 of the side surface 66 of the groove 60 is set to be larger than the friction angle θ0 in the entire range from the inlet 60b to the bottom 60a of the groove 60. From another point of view, it can be said that the inclination angle θ1 of the groove width changing surface 70 of the side surface 66 of the groove portion 60 is set to be larger than the friction angle θ0.

This advantage will be explained. Consider a case where the telescopic member 32 is caught in the side surface 66 of the groove 60 of the stator 28 and the mover 30 at an intermediate position in the Z direction. In this case, when tension is applied to the telescopic member 32, the telescopic member 32 is guided inward in the Y direction by the side surface 66 (groove width changing surface 70) of the groove portion 60, and the telescopic member 32 is moved toward the bottom side thereof. It becomes easy to slide. Along with this, it becomes easier to stably realize a state in which the telescopic member 32 is arranged on the bottom portion 60a of the groove portion 60 as a portion suitable for suppressing the position fluctuation of the telescopic member 32 in the Y direction.

See FIG. 7. The bottom portions 60a of the plurality of groove portions 60 formed in the plurality of convex portions 38 of the stator 28 are provided so as to line up on a straight line Ls when viewed from the Z direction. The straight line Ls passing through the bottom portions 60a of the plurality of groove portions 60 formed in the stator 28 passes through the center of gravity Cg1 of the stator 28 and is located at the center of the stator 28 in the Y direction when viewed from the Z direction. It is provided in. The center of gravity Cg1 here means the center of gravity formed by the geometric shape of the stator 28 when viewed from the Z direction. Here, the central portion refers to a portion on a straight line extending in the X direction through the center of gravity Cg1 when viewed from the Z direction in the present embodiment. In the present embodiment, the straight line passing over the central portion of the stator 28 coincides with the above-mentioned straight line Ls, but these do not have to coincide.

Further, the bottom portions 60a of the plurality of groove portions 60 formed in the plurality of convex portions 40 of the mover 30 are provided so as to line up on a straight line Ls when viewed from the Z direction. The straight line Ls passing through the bottom portions 60a of the plurality of groove portions 60 formed in the mover 30 passes through the center of gravity Cg2 of the mover 30 and is located at the center of the mover 30 in the Y direction when viewed from the Z direction. It is provided in. The center of gravity Cg2 here means the center of gravity formed by the geometric shape of the mover 30 when viewed from the Z direction. Here, the central portion refers to a portion on a straight line extending in the X direction through the center of gravity Cg2 when viewed from the Z direction in the present embodiment. In the present embodiment, the straight line passing over the central portion of the mover 30 coincides with the above-mentioned straight line Ls, but these do not have to coincide.

The bottom portion 60a of the groove portion 60 here does not refer only to the deepest portion 68 of the groove portion 60 in the cross section orthogonal to the X direction, but the depth Dp of the groove portion 60 from the deepest portion 68 of the groove portion 60 (see FIG. 6). It means a part within the range of 0.1 times. The depth Dp here means a dimension along the Z direction from the inlet portion 60b of the groove portion 60 to the deepest portion 68 in a cross section orthogonal to the X direction. For example, when a concave curved surface 74 (second embodiment) is provided at a portion including the deepest portion 68 of the groove portion 60, or when the groove portion 60 is a V-shaped groove, a part of the bottom portion 60a of the groove portion 60 other than the deepest portion 68 is provided. Is to become.

As a result, by arranging the expansion / contraction member 32 so as to pass through the inside of the bottom portion 60a of the groove portion 60, the expansion / contraction member 32 can be arranged so as to pass through a portion close to the straight line Ls when viewed from the Z direction. That is, the telescopic member 32 can be easily arranged linearly when viewed from the Z direction while passing through the bottom portions 60a of the plurality of groove portions 60 which are suitable for suppressing the position fluctuation of the telescopic member 32 in the Y direction. Therefore, by suppressing the fluctuation of the position of the expansion / contraction member 32 in the Y direction by the groove portion 60, it is possible to prevent the expansion / contraction member 32 from meandering greatly, and it is possible to suppress the fluctuation of the output characteristic of the actuator 10 due to the meandering.

Further, according to the configuration of the present embodiment, there are the following advantages. Hereinafter, the positional relationship of the mover 30 as viewed from the Z direction will be described. In addition to the force that translates the mover 30 in the Z direction, a moment that rotates the mover 30 around the axis in the X direction acts on the mover 30 from the telescopic member 32. When the telescopic member 32 deviates from the above-mentioned line Ls in the Y direction, this moment increases in proportion to the amount of the deviation. If this moment increases, the mover 30 will be separated from the stator 28 due to the rotation of the mover 30, which may adversely affect the operation stability.

Here, according to the present embodiment, the straight line Ls passing through the bottoms 60a of the plurality of groove portions 60 of the mover 30 passes through the center of gravity Cg2 of the mover 30 and is located at the center of the mover 30 in the width direction Y. It is provided to do so. Therefore, by arranging the telescopic member 32 so as to pass through the inside of the groove portion 60 of the mover 30, the telescopic member 32 can be arranged so as to pass through a position substantially overlapping the above-mentioned straight line Ls passing through the center of gravity Cg2 of the mover 30. Along with this, the moment applied to the mover 30 from the telescopic member 32 can be suppressed, and the influence of the moment on the operation stability can be easily suppressed.

Refer to FIGS. 8 and 9. The plurality of groove portions 60 formed in the plurality of convex portions 38 and 40 are referred to as end side groove portions (hereinafter, referred to as end side groove portions 72 to distinguish them from other groove portions 60) in the end side groove portions 40 formed in the end side convex portions 40 in the X direction. ) Is included. The end side groove portion 72 of the present embodiment is formed on the second convex portion 40 on the end side of the mover 30 in the X direction.

On the side surface 66 of the end side groove portion 72, a continuous surface 72a is provided on the outer portion (left portion in FIG. 8A) of the convex portion 40 in the X direction. The continuous surface 72a is formed so as to continuously narrow the groove width of the end side groove portion 72 as it approaches the inside in the X direction when viewed from the Z direction. The continuous surface 72a of the present embodiment has a curved surface shape that is convex inward in the Y direction when viewed from the Z direction, but may be a flat surface shape. Here, the inside in the X direction means a side approaching another groove 60 adjacent to the end gutter 72 (right side in FIG. 8A). The outside in the X direction refers to a side (left side in FIG. 8A) that is away from the other groove 60 adjacent to the end gutter 72.

This advantage will be explained. FIG. 10A is a diagram showing an end side groove portion 72 of the mover 30 of the first modification. The side surface 66 of the end side groove portion 72 of this example is formed so as to have a constant groove width in the X direction when viewed from the Z direction (viewed from the viewpoint of FIG. 10A). The convex portion 40 of the mover 30 is formed with an edge portion 40b formed by the outer surface 40a of the convex portion 40 in the X direction and the side surface 66 of the end side groove portion 72.

Outside the end side groove portion 72 in the X direction, the position of the telescopic member 32 may fluctuate in the Y direction. This is caused, for example, by changing the winding position of the telescopic member 32 with respect to the shaft portion of the first fixing member 50. When the position of the expansion / contraction member 32 fluctuates, there is an edge portion 40b at the end of the end side groove portion 72 in the X direction, and when the expansion / contraction member 32 comes into contact with the edge portion 40b, the expansion / contraction member 32 becomes excessive. There is a burden (see FIG. 10 (A)).

In this regard, according to the present embodiment, even if the position of the telescopic member 32 fluctuates in the Y direction outside the end side groove portion 72 in the X direction, the contact point of the stretchable member 32 with respect to the end side groove portion 72 is set to the end. The continuous surface 72a of the gutter portion 72 can be easily formed (see FIG. 10B). Therefore, it becomes easy to avoid the situation where the contact point with the telescopic member 32 becomes the edge portion 40b. Therefore, in arranging the expansion / contraction member 32 on the straight line Ls described above, it is possible to avoid an excessive load on the expansion / contraction member 32 due to the contact between the expansion / contraction member 32 and the edge portion 40b.

(Second Embodiment)
See FIG. In this embodiment, the shapes of the groove 60 of the stator 28 and the mover 30 are different from those in the first embodiment. A concave curved surface 74 is provided on the bottom portion 60a of the groove portion 60 of the present embodiment. The deepest portion 68 of the groove portion 60 of the present embodiment is formed by a part of a concave curved surface 74 located at the deepest portion in the depth direction of the groove portion 60. The radius of curvature of the concave curved surface 74 is set to be larger than the radius of curvature of the circular shape formed by the cross-sectional shape of the telescopic member 32. As a result, as described in the first embodiment, the groove portion 60 of the present embodiment is set to a shape in which the stretchable member 32 in the undeformed state can contact the deepest portion 68 of the groove portion 60.

Although only the groove 60 of the stator 28 is shown in this figure, the groove 60 of the stator 30 has the same shape.

Other modifications of each component will be described.

Although the example in which the actuator 10 is used for the tactile sensation imparting device has been described, its use is not particularly limited. The actuator 10 may be used, for example, as a simple driving device.

Although the example in which the drive target 14 is a touch panel has been described, the driving target 14 is not limited to this. For example, a switch such as an on / off switch may be used.

The shape of the stator 28 is not particularly limited. The stator 28 may have a long shape extending in a curved line as well as in a case where the stator 28 extends linearly. The same applies to the mover 30.

The composition of the shape memory alloy constituting the telescopic member 32 is not particularly limited, and a Ni—Ti—Cu based alloy may be used.

An example in which the groove 60 is formed in each of the plurality of first convex portions 38 and each of the plurality of second convex portions 40 has been described. In addition to this, the groove portion 60 may be formed only in a part of the plurality of first convex portions 38 or a part of the plurality of second convex portions 40.

The groove portion 60 may be formed so that the groove width becomes continuously narrower toward the bottom side in a part of the entire range from the inlet portion 60b to the bottom portion 60a of the groove portion 60. For example, a range of half or more of the above-mentioned total range may be formed so as to satisfy this condition. In this range, the groove width changing surface 70 described above may be provided. Further, the groove portion 60 may be formed so that the groove width gradually narrows toward the bottom side thereof.

The inclination angle θ1 of the side surface 66 of the groove portion 60 may be set to be larger than the friction angle θ0 in a part of the entire range from the inlet portion 60b to the bottom portion 60a of the groove portion 60. For example, a range of half or more of the above-mentioned total range may be set to satisfy this condition.

The groove portion 60 may be set in a shape in which the stretchable member 32 in the undeformed state cannot contact the deepest portion 68 of the groove portion 60. The inclination angle θ1 of the side surface 66 of the groove portion 60 may be set to the friction angle θ0 or less.

The plurality of groove portions 60 formed in the plurality of convex portions 38 and 40 may not be provided so that their bottom portions 60a are aligned on the straight line Ls when viewed from the Z direction. For example, the plurality of groove portions 60 may extend in the X direction while meandering in a zigzag manner when viewed from the Z direction.

The end side groove portion 72 may be formed not in the second convex portion 40 of the mover 30 but in the first convex portion 38 of the stator 28.

The embodiments and modifications of the present invention have been described in detail above. The above-described embodiments and modifications are merely specific examples for carrying out the present invention. The contents of the embodiments and modifications do not limit the technical scope of the present invention, and many design changes such as modification, addition, and deletion of components can be made without departing from the idea of the invention. In the above-described embodiment, the content that can be changed in design is emphasized by adding the notation "embodiment", but the design change is permitted even if the content does not have such a notation. Any combination of the above components is also valid as an aspect of the present invention. The hatching attached to the cross section of the drawing does not limit the material of the object to which the hatching is attached.

10 ... Actuator, 14 ... Drive target, 18 ... Touch detection unit, 20 ... Control unit, 26 ... Telescopic member, 28 ... Stator, 30 ... Movable element, 32 ... Telescopic member, 38 ... First convex part, 40 ... No. 2 Convex part, 60 ... Groove part, 60a ... Bottom part, 66 ... Side surface, 68 ... Deepest part, 72 ... End side groove part, 72a ... Continuous surface.

Claims (7)

With a long stator and
A mover arranged so as to face the stator in a direction orthogonal to the longitudinal direction of the stator and movable in the direction orthogonal to the stator as a movable direction.
It is equipped with an elastic member made of a shape memory alloy that can expand and contract due to temperature changes.
The stator and the mover are provided with a plurality of convex portions alternately in the longitudinal direction.
The telescopic member is stretched so as to be alternately hung on the convex portion of the stator and the convex portion of the mover.
A groove in which the telescopic member is arranged is formed in the convex portion.
The groove portion is an actuator formed so that the groove width becomes narrower toward the bottom side thereof. The actuator according to claim 1, wherein the groove portion is set in a shape so that the telescopic member in an undeformed state can contact the deepest portion of the groove portion. When the direction orthogonal to the longitudinal direction and the movable direction is referred to as the width direction,
In the cross section orthogonal to the longitudinal direction, the inclination angle θ1 of the side surface of the groove with respect to the direction axis in the width direction is set to be larger than the friction angle θ0 determined based on the static friction coefficient between the telescopic member and the side surface. The actuator according to claim 1 or 2. The actuator according to any one of claims 1 to 3, wherein the plurality of groove portions formed in the plurality of convex portions are provided so that their bottom portions are arranged in a straight line when viewed from the movable direction. When the direction orthogonal to the longitudinal direction and the movable direction is referred to as the width direction,
The straight line passing through the bottoms of the plurality of grooves formed in the actuator passes through the center of gravity of the actuator and is located at the center of the actuator in the width direction when viewed from the movable direction. The actuator according to claim 4. The plurality of groove portions formed in the plurality of convex portions include an end-side groove portion formed in the convex portion on the end side in the longitudinal direction.
On the side surface of the end side groove portion, a continuous surface is provided on the outer portion of the convex portion in the longitudinal direction.
The actuator according to claim 4 or 5, wherein the continuous surface is formed so as to continuously narrow the groove width of the end side groove portion as it approaches the inside in the longitudinal direction when viewed from the movable direction. The actuator according to any one of claims 1 to 6, wherein the drive target can be driven by the contraction deformation of the telescopic member.
A touch detection unit that can detect a touch operation on the drive target by the user,
A tactile sensation imparting device including a control unit capable of contracting and deforming the telescopic member by energizing the telescopic member when a touch operation is detected by the touch detection unit.

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