JP2019115187A - Vibration actuator - Google Patents

Abstract

To provide a low cost vibration actuator which hardly generates abnormal sound and has a simple structure.SOLUTION: A first damper 51 and a second damper 61 are arranged so that swirl arm portions 53, 55 and 57 of a first damper (leaf spring) 55 and swirl arm portions 63, 65 and 67 of a second damper (leaf spring) 61 may be opposite with respect to a swirl direction. The arm portions 53, 55 and 57 of the first damper 55 and the arm portions 63, 65 and 67 of the second damper 61 have a stress concentration portion increasing stress locally when force is applied, and the stress concentration portion of each arm portion is located on a plurality of linear lines orthogonal to a vibration axis O.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration actuator, and more particularly to a vibration actuator having a heavy mover.

In a vibration actuator having a moveable magnet type or moveable coil type mover, a plurality of leaf springs are used to support the mover that reciprocates.
Also, in order to increase the vibration force, a weight may be added to the mover. In this case, the mass of the mover may be heavy, and the leaf spring may not be able to support the mover. In particular, when the mover vibrates in the horizontal direction, the mover supported by the plate spring lowers and contacts the case to generate noise or damage the case or the mover.

  In such a case, the mover may be provided with a shaft extending in the direction along the vibration axis, and the shaft may be supported by bearings (see, for example, Patent Document 1).

Patent No. 4567409 gazette

However, the vibration actuator using the above-described bearing has the following problems.
(1) When the mover vibrates, sliding noise (noise) between the bearing and the shaft is generated.
(2) The bearing structure is required, and the structure is complicated and expensive.

  The present invention has been made in view of the above problems, and an object thereof is to provide a low-cost vibration actuator which is less likely to generate abnormal noise, has a simple structure, and the like.

  A vibration actuator according to claim 1 of the present invention for solving the problem comprises a cylindrical case, an electromagnetic drive unit provided inside the case, and a movable that vibrates along the vibration axis of the case by the electromagnetic drive unit. And a supporting portion disposed on one side and the other side across the mover, to which the mover is attached, an annular portion attached to the inner surface of the case, the supporting portion, and the annular portion. It has a first plate spring and a second plate spring consisting of a plurality of spiral arms connected, and the spiral direction of the spiral arms of the first and second plate springs is opposite. The first and second leaf springs are disposed, and a plurality of arm portions of the first and second leaf springs have stress concentration portions where stress is locally increased when a force is applied, The stress concentration portion of the arm portion is located on a plurality of straight lines orthogonal to the vibration axis. The features.

  Other features of the present invention will become more apparent from the modes for carrying out the invention described below and the accompanying drawings.

When the first and second leaf springs are used so that the spiral direction of the spiral arms is the same, the support portion of the leaf spring rotates within the plane as the thickness direction is displaced. Do. For this reason, the mover rotates in accordance with the displacement in the vibration axis direction.
According to the vibration actuator of the present invention, the mover is arranged by arranging the first and second plate springs such that the spiral directions of the spiral arm portions of the first and second plate springs are reversed. Is not rotated even if it is displaced in the vibration axial direction because it receives torque in the opposite direction from both leaf springs.

  Next, the plurality of arms of the first and second plate springs have stress concentration portions where stress is locally increased when a force is applied, and the stress concentration portions of the respective arms are the vibration It is located on a plurality of straight lines orthogonal to the axis. On the other hand, in the portion adjacent to the stress concentration portion of each arm, the generated stress is a low stress portion smaller than the stress concentration portion, and this low stress portion has a vibration different from the same straight line where the stress concentration portion is located. It is located on a plurality of straight lines orthogonal to the axis. Therefore, the mover is supported by the low stress portions positioned on a plurality of straight lines orthogonal to the vibration axis, and does not tilt relative to the vibration axis even if the mover is displaced in the vibration axis direction.

Therefore, even if the mover is displaced in the vibration axis direction, it does not rotate and does not tilt relative to the vibration axis, so abnormal noise is unlikely to be generated, and a vibration actuator with a simple structure and low cost can be realized.
Other effects of the present invention will become more apparent from the modes for carrying out the invention described below and the attached drawings.

It is an exploded perspective view explaining an embodiment of a vibration actuator of the present invention. It is a top view at the time of assembling | attaching FIG. It is a front view of FIG. It is a rear view of FIG. It is a bottom view of FIG. It is a left view of FIG. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. It is a figure explaining the method to attach a division | segmentation yoke to a case. It is a figure explaining how to attach a coil to the case where division yoke was attached. It is a figure explaining the case where the division | segmentation yoke and the coil were attached. It is a top view of the 1st damper of FIG. When a load is applied only to a 1st damper, it is a top view which shows distribution of the stress which generate | occur | produces in each part. When a load is applied only to a 1st damper, it is a perspective view which shows distribution of the stress which generate | occur | produces in each part, and the displacement of each part. When a load is applied to the 1st and 2nd damper arranged so that the spiral direction of the spiral arm of the 1st and 2nd dampers may become the same, it is a top view showing distribution of stress which occurs in each part . When load is applied to the first and second dampers arranged so that the spiral direction of the spiral arm of the first and second dampers becomes the same, the distribution of the stress generated in each portion and the displacement of each portion are shown. It is a perspective view. When a load is applied to the 1st and 2nd dampers arrange | positioned so that the spiral direction of the spiral arm of a 1st and 2nd damper may become reverse, it is a top view which shows distribution of the stress which generate | occur | produces in each part . Indicates the distribution of stress generated in each part and the displacement of each part when a load is applied to the first and second dampers arranged so that the spiral directions of the spiral arms of the first and second dampers are opposite. It is a perspective view. It is a figure explaining the action | operation of the vibration actuator shown in FIG. It is a figure explaining the operation | movement of the vibration actuator of other embodiment.

Embodiments will be described using the drawings. 1 is an exploded perspective view for explaining an embodiment of a vibration actuator according to the present invention, FIG. 2 is a plan view when FIG. 1 is assembled, FIG. 3 is a front view of FIG. 2 and FIG. 4 is a rear view of FIG. 5 is a bottom view of FIG. 2, FIG. 6 is a left side view of FIG. 3, FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. Fig. 10 illustrates a method of attaching a coil to a case to which a split yoke is attached, Fig. 10 illustrates a case to which a split yoke and a coil are attached, and Fig. 18 illustrates the operation of the vibration actuator shown in Fig. 1 FIG. 19 is a view for explaining the operation of the vibration actuator according to another embodiment. The right side of FIG. 3 is the same as the left side of FIG.
(overall structure)
The entire configuration of the vibration actuator will be described using FIGS. 1 to 7.

A yoke 11 made of a cylindrical soft magnetic material is provided in the inside of a case 1 made of a resin such as ABS having an opening at both ends. The coil 21 is attached to the inner peripheral surface of the yoke 11 in a state of being electrically insulated from the yoke 11.
A cylindrical first cover case 31 made of resin such as ABS is disposed on the end face on one opening side of the case 1. A cylindrical second cover case 41 made of resin such as ABS is disposed on the other open end of the case 1.

  A thin plate of stainless steel is machined on the end face of the first cover case 31 on the opposite side to the case 1, and a first damper 51, which is a leaf spring that is flexible along the oscillation axis O of the case 1, It is arranged. A thin plate of stainless steel is processed on the end face on the opening side of the second cover case 41 opposite to the case 1, and the second damper 61, which is a leaf spring flexible along the vibration axis O of the case 1, It is arranged.

The first damper cover 71 is disposed so as to sandwich the first damper 51 in cooperation with the first cover case 31. The second damper cover 81 is disposed so as to sandwich the second damper 61 in cooperation with the second cover case 41.
Three through holes 71 a are formed along the edge of the first damper cover 71 at a pitch of 120 °. The first cover case 31 is formed with three through holes 31 a facing the holes 71 a of the first damper cover 71. Three female screw holes 1 a facing the three holes 31 a of the first cover case 31 are formed in an end face on one opening side of the case 1.

  Then, the peripheral portion of the first damper 51 is the first by the three screws 91 inserted through the hole 71 a of the first damper cover 71 and the hole 31 a of the first cover case 31 and screwed into the female screw hole 1 a of the case 1. The first damper cover 71, the first damper 51, and the first cover case 31 are attached to one opening side of the case 1 in a state of being held between the first damper cover 71 and the first cover case 31. That is, the first damper 51 is attached to the inner surface of the case 1.

  Three through holes 81 a are formed along the edge of the second damper cover 81 at a pitch of 120 °. The second cover case 41 is formed with three through holes 41 a facing the holes 81 a of the second damper cover 81. Three female screw holes (not shown) facing the three holes 41 a of the second cover case 41 are formed on the other open end of the case 1.

  Then, the third damper 101 is inserted through the hole 81a of the second damper cover 81 and the hole 41a of the second cover case 41, and is formed on the other open end face of the case 1 and thus screwed into the screw hole. The second damper cover 81, the second damper 61, and the second cover case 41 are disposed on the other opening side of the case 1 while the second damper 61 is held between the second damper cover 81 and the second cover case 41. It is attached. That is, the second damper 61 is attached to the inner surface of the case 1.

  Between the first damper 51 and the second damper 61, a mover 111 which is surrounded by the coil 21 and vibrates along the vibration axis O is disposed. The mover 111 includes a disk-shaped magnet 113, and disk-shaped first pole pieces 115 and second pole pieces 117 disposed so as to sandwich the magnet 113, magnets 113, first pole pieces 115, and second It consists of a first mass (weight) 119 and a second mass (weight) 121 disposed so as to sandwich the pole piece 117.

  The magnetizing direction of the magnet 113 is the vibration axis O direction. The first pole piece 115 and the second pole piece 117 are made of a hardly magnetic material, and are attached to the magnet 113 by the magnetic attraction force of the magnet 113, an adhesive agent, and the like. The first mass 119 and the second mass 121 are nonmagnetic materials, and are attached to the first pole piece 115 and the second pole piece 117 by an adhesive or the like. Therefore, the magnet 113 constituting the mover 111, the first pole piece 115, the second pole piece 117, the first mass 119, and the second mass 121 are integrated.

  In the first mass 119 and the second mass 121, a hole 119a penetrating along the central axis and a hole 121a penetrating are formed. Further, at the center of the first damper 51, a hole 51a which is opposed to and penetrates the hole 119a of the first mass 119 is formed. Similarly, in the center of the second damper 61, a hole 61a which is opposed to and penetrates the hole 121a of the second mass 121 is formed.

Then, the pin 131 is inserted through the hole 51 a of the first damper 51 and press-fit into the hole 119 a of the first mass 119, and the pin 141 is inserted through the hole 61 a of the second damper 61 and press-fitted into the hole 121 a of the second mass 121 As a result, the mover 111 is vibratably supported along the oscillation axis O of the case 1.
A first plate spring including a support portion to which the mover is attached, a ring portion attached to the inner surface of the case, and a plurality of spiral arms connecting the support portion and the ring portion; A lead wire is connected to the surface, and a terminal 3 for supplying a current to the coil 21 is formed.
(Case 1, yoke 11, coil 21)
The yoke 11 of the present embodiment, which is described with reference to FIGS. 8 to 10, is configured of a plurality of (three in the present embodiment) divided yokes 13 in a strip shape, in which cylinders are cut along different generating lines.

In addition, the coil 21 of the present embodiment is disposed along the vibration axis O, and includes a first coil 23 and a second coil 25. The first coil 23 and the second coil 25 are wound along the inner circumferential surface of the yoke 11.
On the inner peripheral surface of the case 1, three ribs 5 which protrude in the vibration axis O direction and extend in the vibration axis O direction are formed at equal pitch intervals.

  At two end surfaces in the vibration axis O direction of each rib 5, a divided yoke contact surface 5a is formed, with which the end surface along the generatrix of the divided yoke 13 abuts. In the present embodiment, since the rib 5 is made of resin, it has elasticity. Thus, the two end faces along the generatrix of the split yoke 13 abut.

The end surface of the split yoke 13 along the generatrix abuts against the split yoke contact surface 5 a of the rib 5, whereby positioning of the split yoke 13 in the circumferential direction of the case 1 is achieved.
Further, on the surface 5 b of the mover 111 of each rib 5 facing the magnet 113, a protrusion 7 that protrudes in the direction of the mover 111 is formed. On one opening side of the case 1 of the protrusion 7, a first coil contact surface 7a is formed, with which the end on the opening side of the first coil 23 abuts. On the other opening side of the case 1 of the projection 7, a second coil contact surface 7 b is formed, with which the end on the opening side of the second coil 25 abuts.

The adhesion is performed with the open end of the first coil 23 in contact with the first coil contact surface 7a of the projection 7 of the rib 5 and the first coil 23 positioned in the direction of the vibration axis O of the case 1 The first coil 23 is attached to the yoke 11 using an agent or the like. The adhesion is performed with the open end of the second coil 25 in contact with the second coil contact surface 7b of the protrusion 7 of the rib 5 and the second coil 25 positioned in the direction of the vibration axis O of the case 1 The second coil 25 is attached to the yoke 11 using an agent or the like.
(First damper 51, second damper 61)
The first damper 51 and the second damper 61 of the present embodiment will be described in more detail with reference to FIG. The first damper 51 and the second damper 61 have the same shape and only differ in the way of attachment. Therefore, the first damper 51 will be described here, and the description of the second damper 61 will be omitted. The same parts as those of the first damper 51 of the second damper 61 will be described with reference numerals obtained by adding 10 to the reference numerals of the respective parts of the first damper 51. For example, when the first arm of the first damper 51 is the code 53, the code of the first arm of the second damper 61 is 63.

At a central portion of the first damper 51, a support portion 51b attached to the mover 111 using a pin 131 inserted through the hole 51a is formed.
In order to prevent interference with the screw 91, three notches 51d are provided in the annular portion 51c of the first damper 51 held by the first damper cover 71 and the first cover case 31 and attached to the inner surface of the case 1 It is formed.

The support portion 51 b and the annular portion 51 c are connected by three identical spiral first arm portions 53, second arm portions 55, and third arm portions 57. The first arm 53, the second arm 55, and the third arm 57 are provided at a pitch of 120 ° around the vibration axis O.
The first arm portion 53 has a curvature larger than that of the other portions, and a first stress concentration portion 53a, a second stress concentration portion 53b, and a third stress concentration portion 53c in which stress locally increases when a force is applied. have. Similarly, the second arm 55 has a curvature larger than that of the other portions, and the first stress concentration portion 55a, the second stress concentration portion 55b, and the third stress in which stress locally increases when a force is applied. The third arm portion 57 has a concentrated portion 55c, the curvature of which is larger than that of the other portions, and the first stress concentrated portion 57a and the second stress concentrated portion 57b in which stress locally increases when a force is applied. , And a third stress concentration portion 57c.

  The first stress concentration portion 53a of the first arm portion 53, the second stress concentration portion 57b of the third arm portion 57, and the third stress concentration portion 55c of the second arm portion 55 are orthogonal to the vibration axis O. Located on the first straight line L1. In addition, the first stress concentration portion 55a of the second arm portion 55, the second stress concentration portion 53b of the first arm portion 53, and the third stress concentration portion 57c of the third arm portion 57 are orthogonal to the vibration axis O Are located on the second straight line L2. Furthermore, the first stress concentration portion 57a of the third arm portion 57, the second stress concentration portion 55b of the second arm portion 55, and the third stress concentration portion 53c of the first arm portion 55 are orthogonal to the vibration axis O. Located on the third straight line L3. The first straight line L1, the second straight line L2, and the third straight line L3 are located at a pitch of 120 ° around the vibration axis O.

This configuration also has a second damper 61.
And as shown in FIG. 1, the spiral direction of the 1st arm 53 of the 1st damper 51, the 2nd arm 55, the 3rd arm 57, the 1st arm 63 of the 2nd damper 61, the 2nd arm The first damper 51 and the second damper 61 are disposed such that the spiral direction of the portion 65 and the third arm 67 is opposite to each other.

(Operation)
The operation of the vibration actuator of the present embodiment will be described with reference to FIG.
When the first coil 23 and the second coil 25 are not energized, the mover 111 supported by the first damper 51 and the second damper 61 is located at the center of the coil 21.

An alternating current is supplied to the first coil 23 and the second coil 25 in a direction to generate magnetic fields of opposite polarity alternately. That is, the same pole is generated at adjacent portions of the first coil 23 and the second coil 25.
In the polarity of FIG. 18, a downward thrust (direction of arrow A) is generated in the mover 111, and the current flowing to the first coil 23 and the second coil 25 is reversed. Thrust in the direction of arrow B) is generated.

As described above, when alternating current is supplied to the first coil 23 and the second coil 25, the movable element 111 receives the urging force from the both sides by the case 1, the first damper 51, and the second damper 61. Vibrate along.
By the way, the thrust generated in the mover 111 is basically based on the thrust given based on Fleming's left-hand rule. In the present embodiment, since the first coil 23 and the second coil 25 are fixed, a thrust as a reaction force of the force generated in the first coil 23 and the second coil 25 is generated in the mover 111.

Thus, it is the horizontal component of the magnetic flux of the magnet 113 of the mover 111 (component orthogonal to the axial direction of the magnet 113) that contributes to the thrust. The yoke 11 is to increase the horizontal component of the magnetic flux of the magnet 113.
According to the above configuration, the following effects can be obtained.

 (1) The spiral direction of the first arm 53, the second arm 55, and the third arm 57 of the first damper 51, and the first arm 63, the second arm 65, and the third arm of the second damper 61 When the spiral direction of the portion 67 is arranged to be the same, the support portion 51b of the first damper 51 and the support portion 61b of the second damper 61 rotate in the plane as the displacement in the thickness direction. try to. For this reason, the mover 11 rotates in accordance with the displacement in the direction of the vibration axis O.

  In the present embodiment, the spiral direction of the first arm 53, the second arm 55, and the third arm 57 of the first damper 51, and the first arm 63, the second arm 65, and the second of the second damper 61. The first damper 51 and the second damper 61 are disposed such that the direction in which the three arm portion 67 swirls is opposite, so that the mover 111 receives torque in the reverse direction from the first damper 51 and the second damper 61. It does not rotate even if it is displaced in the direction of the vibration axis O in order to receive the

  In addition, the first arm 53 has a curvature larger than that of other portions, and the first stress concentration portion 53a, the second stress concentration portion 53b, and the third stress concentration where stress is locally increased when a force is applied. It has a portion 53c. Similarly, the second arm 55 has a curvature larger than that of the other portions, and the first stress concentration portion 55a, the second stress concentration portion 55b, and the third stress in which stress locally increases when a force is applied. The third arm portion 57 has a concentrated portion 55c, the curvature of which is larger than that of the other portions, and the first stress concentrated portion 57a and the second stress concentrated portion 57b in which stress locally increases when a force is applied. , And a third stress concentration portion 57c.

  The first stress concentration portion 53a of the first arm portion 53, the second stress concentration portion 57b of the third arm portion 57, and the third stress concentration portion 55c of the second arm portion 55 are orthogonal to the vibration axis O. Located on the first straight line L1. In addition, the first stress concentration portion 55a of the second arm portion 55, the second stress concentration portion 53b of the first arm portion 53, and the third stress concentration portion 57c of the third arm portion 57 are orthogonal to the vibration axis O Are located on the second straight line L2. Furthermore, the first stress concentration portion 57a of the third arm portion 57, the second stress concentration portion 55b of the second arm portion 55, and the third stress concentration portion 53c of the first arm portion 55 are orthogonal to the vibration axis O. Located on the third straight line L3.

  On the other hand, in the portion adjacent to the stress concentration portion of each arm, the generated stress is a low stress portion smaller than the stress concentration portion, and the low stress portion has the same straight line L1, L2, L3 where the stress concentration portion is located. And a plurality of straight lines L4, L5, L6 positioned at a pitch of 120 ° around the vibration axis O (the straight lines L4, L5, L6 indicated by broken lines in FIG. 11). reference). Therefore, the mover 111 is supported by low stress portions located on straight lines L4, L5, L6 orthogonal to the vibration axis O, and the mover 111 is displaced in the direction of the vibration axis O with respect to the vibration axis O I do not lean.

Therefore, even if the mover 111 is displaced in the direction of the vibration axis O, the mover 111 does not rotate and does not tilt relative to the vibration axis O, so abnormal noise hardly occurs, and the structure is simple and the cost is low. An actuator can be realized.
The present invention is not limited to the above embodiment.

In the said embodiment, although the stress concentration part was formed by making curvature of an arm larger than another part, it does not limit to curvature. For example, even if a hole or a notch is provided in the arm, the stress concentration portion can be formed.
Moreover, in the said embodiment, although three stress concentration parts were formed in each arm, it may not be three but multiple, ie, 2 or 4 or more may be sufficient.

  Furthermore, in the above-described embodiment, the example in which the coil 21 is composed of the first coil 23 and the second coil 25 has been described, but as shown in FIG. 19, one coil 221 may be used. In this case, the magnet of the mover 311 is magnetized in the radial direction.

The applicant analyzed the displacement and stress when a load was applied to the first damper 51 and the second damper 61 using the finite element method in order to confirm the effect of the present invention.
The first damper 51 and the second damper 61 were made of a material of SUS 304, a thickness of 0.3 mm, and a weight of 100 g, and analysis was performed using shell elements.

(1) Analysis when a load is applied only to the first damper 51
When a load of 2.1 N was applied to the support portion 51b of the first damper 51, the maximum displacement was 1.981 mm and the maximum stress was 318 MPa.
The analysis results are shown in FIG. 12 and FIG. FIG. 12 is a plan view showing the distribution of stress generated in each part when a load is applied only to the first damper, and FIG. 13 is a distribution of stress generated in each part when a load is applied only to the first damper and It is a perspective view which shows a displacement.

The stress distribution indicates that the higher the black density, the higher the stress. Moreover, the part in which the mesh is not cut has shown the initial state (unloaded state).
As shown in FIG. 12, the second stress concentration portion 53b and the third stress concentration portion 53c of the first arm portion 53 of the first damper 51, the second stress concentration portion 55b of the second arm portion 55, and the third stress concentration portion 55c, it can be seen that the second stress concentration portion 57b and the third stress concentration portion 57c of the third arm portion 57 are dark and high stress is generated. On the other hand, it is understood that the portion adjacent to the stress concentration portion of each arm portion is light in color, and the generated stress is a small low stress portion compared to the stress concentration portion.

Further, as shown in FIG. 13, it can be seen that the displacement of the support portion 51b is the largest.
Furthermore, as shown in FIGS. 12 and 13, when a load is applied, the support portion 51b of the first damper 51, the first arm 53, the second arm 55, and the third arm 57 have a fixed circle. It can be seen that the ring portion 51c is displaced from the no-load state.

(2) Analysis when load is applied to the first and second dampers arranged so that the spiral directions of the spiral arms of the first and second dampers become the same It demonstrates using. FIG. 14 shows a distribution of stress generated in each portion when a load is applied to the first and second dampers arranged such that the spiral directions of the spiral arm portions of the first and second dampers become the same. Top view, FIG. 15 shows distribution of stress generated in each part when load is applied to the first and second dampers arranged so that the spiral direction of the spiral arms of the first and second dampers become the same. And a perspective view showing displacement of each part.

The stress distribution indicates that the higher the black density, the higher the stress. Moreover, the part in which the mesh is not cut has shown the initial state (unloaded state).
In this analysis, the first damper 51 and the second damper 61 are disposed along the vertical line, the mass of the mover 111 located along the horizontal line is set to 100 g, the gravity is set to 1 G, and the load of 4.4 N is the first The support 51 b of the damper 51 was added. Then, the maximum displacement of the first damper 51 and the second damper 61 was 1.988 mm, and the maximum stress was 329 MPa.

  As shown in FIG. 14, the second stress concentration portion 53b and the third stress concentration portion 53c of the first arm portion 53 of the first damper 51, the second stress concentration portion 55b of the second arm portion 55, and the third stress concentration portion 55c, it can be seen that the second stress concentration portion 57b and the third stress concentration portion 57c of the third arm portion 57 are dark and high stress is generated. Similarly, the second stress concentration portion 63b and the third stress concentration portion 63c of the first arm portion 63 of the second damper 61, and the second stress concentration portion 65b and the third stress concentration portion 65c of the second arm portion 65. It can be seen that the second stress concentration portion 67 b and the third stress concentration portion 67 c of the arm portion 67 are dark and high stress is generated. On the other hand, it is understood that the portion adjacent to the stress concentration portion of each arm portion is light in color, and the generated stress is a small low stress portion compared to the stress concentration portion.

Moreover, as shown in FIG. 15, it turns out that the displacement of the support part 51b and the support part 61b is the largest.
Furthermore, as shown in FIG. 14, the side portions of the first arm 53, the second arm 55, and the third arm 57 in no load, and the first arm 53, second arm 55, in load, Between the side portions of the third arm portion 57, a gap S1 having no parallel portion is generated. The gap S1 is generated by the low stressed portions of the respective arms moving toward the support portion 51b (center) when a load is applied to the first damper 51. At that time, since the support portion 51b, the first arm portion 53, the second arm portion 55, and the third arm portion 57 are rotated with respect to the fixed annular portion 51c, the gap S1 having no parallel portion It becomes.

That is, when a load is applied to the first damper 51, the support portion 51b, the first arm 53, the second arm 55, and the third arm 57 rotate with respect to the fixed annular portion 51c. I understand that.
Similarly, the supporting portion 61b of the second damper 61, the first arm 63, the second arm 65, and the third arm 67 are also rotated from a no-load state with respect to the fixed annular portion 61c. I understand.

(3) Analysis when a load is applied to the first and second dampers arranged such that the spiral direction of the spiral arm of the first and second dampers is opposite (corresponding to the embodiment)
The analysis result is described with reference to FIGS. FIG. 16 is a plane showing the distribution of stress generated in each portion when a load is applied to the first and second dampers arranged so that the spiral direction of the spiral arm of the first and second dampers is reversed. FIG. 17 shows the distribution of stress generated in each portion when a load is applied to the first and second dampers arranged so that the spiral direction of the spiral arm of the first and second dampers is reversed. It is a perspective view which shows the displacement of each part.

The stress distribution indicates that the higher the black density, the higher the stress. Moreover, the part in which the mesh is not cut has shown the initial state (unloaded state).
In this analysis, the first damper 51 and the second damper 61 are disposed along a vertical line, the mass of the mover 111 located along the horizontal line is set to 100 g, the gravity is set to 1 G, and the load of 4.7 N is The support 51 b of the damper 51 was added. Then, the maximum displacement of the first damper 51 and the second damper 61 was 1.985 mm, and the maximum stress was 444 MPa.

  As shown in FIG. 16, the second stress concentration portion 53b and the third stress concentration portion 53c of the first arm portion 53 of the first damper 51, and the second stress concentration portion 55b of the second arm portion 55 and the third stress concentration portion 55c, it can be seen that the second stress concentration portion 57b and the third stress concentration portion 57c of the third arm portion 57 are dark and high stress is generated. Similarly, the second stress concentration portion 63b and the third stress concentration portion 63c of the first arm portion 63 of the second damper 61, and the second stress concentration portion 65b and the third stress concentration portion 65c of the second arm portion 65. It can be seen that the second stress concentration portion 67 b and the third stress concentration portion 67 c of the arm portion 67 are dark and high stress is generated. On the other hand, it is understood that the portion adjacent to the stress concentration portion of each arm portion is light in color, and the generated stress is a small low stress portion compared to the stress concentration portion.

Further, as shown in FIG. 17, it can be seen that the displacement of the support portion 51 b and the support portion 61 b is the largest.
Furthermore, as shown in FIG. 16, the side portions of the first arm 53, the second arm 55, and the third arm 57 in no load, and the first arm 53, the second arm 55, in the load, Between the side portions of the third arm portion 57, a gap S2 having a portion substantially parallel to the middle portion is generated. The gap S2 is generated by the low stressed portions of the respective arms moving toward the support portion 51b (center) when a load is applied to the first damper 51. At that time, since the support portion 51b, the first arm portion 53, the second arm portion 55, and the third arm portion 57 do not rotate with respect to the fixed annular portion 51c, they have portions substantially parallel to the intermediate portion. It becomes gap S2.

That is, when a load is applied to the first damper 51, the support portion 51b, the first arm 53, the second arm 55, and the third arm 57 do not rotate with respect to the fixed annular portion 51c. I understand.
Similarly, it can be seen that the support portion 61b, the first arm 63, the second arm 65, and the third arm 67 of the second damper 61 do not rotate from a no-load state with respect to the fixed annular portion 61c. .

1 case 11 yoke 13 split yoke 21 coil 51 first damper (leaf spring)
53, 63 first arm 55, 65 second arm 57, 67 third arm 61 second damper (leaf spring)
111 mover 113 magnet

Claims (3)

With a cylindrical case,
An electromagnetic drive unit provided inside the case;
A mover that vibrates along a vibration axis of the case by the electromagnetic drive unit;
A plurality of support portions disposed on one side and the other side of the mover, the support portion to which the mover is attached, an annular portion attached to the inner surface of the case, and a plurality of connecting the support portion and the annular portion A first plate spring and a second plate spring, each of which comprises a spiral arm of
Have
The first and second leaf springs are arranged such that the spiraling direction of the spiral arms of the first and second leaf springs is reversed,
The plurality of arms of the first and second leaf springs have a stress concentration portion where stress is locally increased when a force is applied,
The stress concentration portion of each arm is located on a plurality of straight lines orthogonal to the vibration axis.   The vibration actuator according to claim 1, wherein the straight lines on which the stress concentration portions of the arm portions of the first and second plate springs are located are three at a pitch of 120 ° around the vibration axis.   The vibration actuator according to claim 1, wherein the stress concentration portion of the arm portion has a curvature larger than that of the front and rear portions.