Patent Publication Number: US-10770991-B2

Title: Vibrator manufacturing method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/612,151, filed Feb. 2, 2015, which claims priority to U.S. Pat. No. 8,981,619, issued Mar. 17, 2015, which claims priority from Japanese Patent Application No. 2010-087891 filed Apr. 6, 2010, all of which are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a vibration type actuator generating vibration in a vibrator to cause a driven body to make a relative movement, a vibrator of a vibration type actuator, and a vibrator manufacturing method. 
     Description of the Related Art 
     In a vibration type actuator, a contact portion to be brought into press contact is endowed with resiliency, whereby a smooth contact can be realized, and a satisfactory performance can be obtained. As illustrated in  FIG. 11 , in a linear vibration type actuator discussed in Japanese Patent Application Laid-Open No. 2008-125147, a vibrator  110  is provided with protrusions  119  each equipped with a contact portion  113  exhibiting resiliency. 
     The protrusion  119  is composed of the contact portion  113  having a contact surface  114  to be brought into contact with a driven body (not illustrated), a fixation portion  117 , and a connection portion  116  connecting the contact portion  113  and the fixation portion  117 , and the fixation portion  117  is fixed to an elastic member  112  by laser welding or the like. In order that the contact portion  113  may exhibit resiliency, the elastic member  112  is provided with a groove portion  118  of a sufficient depth. The elastic member  112  is provided on a piezoelectric member  115 . 
     The provision of a vibrator with a contact portion with resiliency is not limited to a linear vibration type actuator. As discussed in Japanese Patent Application Laid-Open No. 2006-311790, there exists a rotary vibration type actuator for generating a progressive wave in an elastic member whose vibrator has at the distal end of a protrusion thereof a resilient contact portion joined thereto. 
     However, the conventional constructions described above have the following problems. In the linear vibration type actuator discussed in Japanese Patent Application Laid-Open No. 2008-125147, to increase the moving speed of the driven body, it is necessary to heighten the contact surfaces  114  of the vibrator  110 , which are brought into contact with the driven body, to thereby enlarge the vibration amplitude in the feeding direction (the X-direction). 
     However, heightening the contact surface  114  results in a reduction in the rigidity in the X-direction of the connection portions  116 , so that, although high vibration speed can be attained, it is difficult to transmit drive force efficiently to the driven body. Further, since the resonance frequency of the vibration mode in which the protrusions  119  vibrate is reduced, unnecessary vibration is likely to be generated, so that, in some cases, it is difficult to obtain a satisfactory actuator performance. 
     Also regarding the rotary vibration type actuator as discussed in Japanese Patent Application Laid-Open No. 2006-311790, heightening the contact surfaces results in a reduction of the rigidity in the peripheral and radial directions, and unnecessary vibration may easily occur. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, a vibration type actuator includes a vibrator equipped with an electrical-mechanical energy conversion element, an elastic member to which the electrical-mechanical energy conversion element is fixed, and a protrusion provided on the elastic member, and the vibrator being configured to generate an elliptic movement in the protrusion, and a driven body configured to contact with the protrusion and to move relatively to the vibrator, wherein the protrusion includes a contact portion having a contact surface contacting the driven body, a continuous side wall portion protruding with respect to one end surface of the elastic member and forming a hollow structure, and a connection portion connecting the contact portion and the side wall portion and exhibiting flexibility in a direction normal to the contact surface. 
     According to another aspect of the present invention, a vibrator includes an electrical-mechanical energy conversion element, an elastic member to which the electrical-mechanical energy conversion element is fixed, and a protrusion provided on the elastic member, is the vibrator being configured to generate an elliptic movement in the protrusion to thereby cause a driven body to make a relative movement, wherein the protrusion includes a contact portion having a contact surface contacting the driven body, a continuous side wall portion protruding with respect to one end surface of the elastic member and forming a hollow structure, and a connection portion connecting the contact portion and the side wall portion and exhibiting flexibility in a direction normal to the contact surface. 
     According to yet another aspect of the present invention, a method of manufacturing a vibrator equipped with an electrical-mechanical energy conversion element, an elastic member to which the electrical-mechanical energy conversion element is fixed, and a protrusion provided on the elastic member, and the vibrator being configured to cause a driven body contacting the protrusion to make a relative movement, includes performing press molding on the elastic member to thereby form a continuous side wall portion protruding from the elastic member and forming a hollow structure, a contact portion having a contact surface configured to contact the driven body, and a connection portion configured to connect the side wall portion and the contact portion and have flexibility in a direction normal to the contact surface, and punching the elastic member to shape the vibrator. 
     According to the present invention, the side surface of the protrusion is continuously connected with the contact surface of the protrusion of the vibration type actuator while exhibiting resiliency in the Z-direction, so that it is possible to ensure rigidity in the X- and Y-directions, thereby making it possible to obtain a satisfactory actuator performance. 
     Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a perspective view of a vibrator according to a first exemplary embodiment of the present invention, and 
         FIG. 1B  is a perspective view, partly in section, of a protrusion thereof. 
         FIG. 2A  is a perspective view of a vibrator according to a second exemplary embodiment of the present invention, and 
         FIG. 2B  is a perspective view, partly in section, of a protrusion thereof. 
         FIG. 3A  is a perspective view of a vibrator according to a third exemplary embodiment of the present invention, and 
         FIG. 3B  is a perspective view, partly in section, of a protrusion thereof. 
         FIG. 4  is a perspective view of a ring-shaped vibrator according to a fourth exemplary embodiment of the present invention. 
         FIG. 5A  is a perspective view of a vibrator according to a fifth exemplary embodiment of the present invention, and 
         FIG. 5B  is a perspective view, partly in section, of a protrusion thereof. 
         FIGS. 6A to 6F  are diagrams illustrating an integral press molding process performed on an elastic member. 
         FIG. 7A  is a perspective view of a vibrator according to a sixth exemplary embodiment of the present invention, and 
         FIG. 7B  is a perspective view, partly in section, of a protrusion thereof. 
         FIGS. 8A to 8E  are diagrams illustrating an integral press molding process performed on the elastic member of FIGS.  7 A and  7 B. 
         FIG. 9  is an external perspective view of a conventional linear vibration type actuator. 
         FIGS. 10A and 10B  are diagrams illustrating two vibration modes in which excitation is effected by the vibrator of  FIG. 9 . 
         FIG. 11  is a perspective view of a vibrator on which protrusions with resiliency are mounted, and of one of the protrusions. 
         FIG. 12A  is a perspective view of a vibrator according to a modification example of the fifth exemplary embodiment of the present invention, and  FIG. 12B  is a perspective view, partly in section, of a protrusion thereof. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. 
     In a first exemplary embodiment, a vibrator applicable to a linear vibration type actuator will be described. First, the driving principle thereof will be described with reference to  FIGS. 9, 10A, and 10B . 
       FIG. 9  is a schematic perspective view of a linear vibration type actuator. In  FIG. 9 , a linear vibration type actuator  200  is composed of a vibrator  100  and a slider  106  constituting a driven body. The vibrator  100  has a piezoelectric element  105 , which is an electrical-mechanical energy conversion element formed as a rectangular thin plate, an elastic member  102  joined to one end surface of the piezoelectric element  105 , and two protrusions  103  formed so as to protrude from the elastic member  102 . 
       FIGS. 10A and 10B  are diagrams illustrating how the vibrator illustrated in  FIG. 9  is deformed through excitation in two vibration modes (MODE-A and MODE-B), respectively. Here, both of the two vibration modes are bending vibration modes in out-of-plane directions with respect to the vibrator  100 . The configuration of the vibrator  100  is selected so that the resonance frequencies substantially coincide with each other. 
     The two diagrams located downside in  FIG. 10A  illustrate the vibrator  100  as seen from the Y-direction. As illustrated in the diagram at the bottom of  FIG. 10A , the vibration of MODE-A is a vibration of a secondary bending vibration mode in which there appear three nodes (α), which extend in the Y-direction of the vibrator  100 . 
     The protrusions  103  are arranged at positions in the vicinity of the nodes in the vibration of MODE-A, and in the vibration of MODE-A, there is generated in them a reciprocating movement causing the contact surfaces to be displaced in the X-direction (a direction which is parallel to the contact surfaces and which constitutes the driven body feeding direction) as indicated by the arrows. 
     The two diagrams located downside in  FIG. 10B  illustrate the vibrator  100  as seen from the X-direction. As illustrated in the diagram at the bottom of  FIG. 10B , the vibration of MODE-B is a vibration of a primary bending vibration mode in which there appear two vibration nodes (β), which extend in the X-direction of the vibrator  100 . That is, the vibration nodes of MODE-A and the vibration nodes of MODE-B are orthogonal to each other in an XY-plane. 
     As illustrated in  FIG. 10B , the protrusions  103  are situated in the vicinity of positions constituting the antinodes in the vibration of MODE-B, and through the vibration of MODE-B, there is generated in the protrusions  103  a reciprocating movement causing the contact surfaces to be displaced in the Z-direction (a direction which is perpendicular to the contact surfaces and which is a push-up direction) as indicated by the arrow. 
     When AC signals differing in time phase by approximately π/2 are input to two electrodes (not illustrated) provided in the piezoelectric element  105 , vibrations of MODE-A and MODE-B described above are generated through excitation in the vibrator  100  in such a manner that the difference in time phase is approximately ±π/2. The vibrations of the two vibration modes are synthesized, whereby an elliptic movement in the XZ-plane in  FIG. 9  is generated in the contact surfaces  104  of the protrusions  103 . Due to this elliptic movement, the slider  106 , which is brought into press contact with the contact surfaces  104 , makes a relative movement with respect to the vibrator  100 . 
     It should be noted, however, that, in the linear vibration type actuator of the present exemplary embodiment, the method of generating an elliptic movement in the contact surfaces is not limited to the above-described one. For example, it is also possible to combine with each other vibrations of vibration modes different from the above-described ones, or to combine with each other a vibration of a vertical vibration mode expanding and contracting the elastic member in the X-direction and a vibration of a bending vibration mode. 
     In other words, it is possible to adopt any type of drive system so long as it is one generating an elliptic movement in the contact surfaces through combination of a vibration substantially of a vibration mode for displacing the contact surfaces in the feeding direction and a vibration in a vibration mode for displacing the contact surfaces in the pushing-up direction. 
     Next, a specific construction of the vibrator of the first exemplary embodiment will be described.  FIG. 1A  is a perspective view of a vibrator to which the first exemplary embodiment of the present invention is applicable, and  FIG. 1B  is a perspective view, partly in section, of a protrusion thereof. The actuator of the present exemplary embodiment is a linear vibration type actuator. As its driving principle, the drive system of the conventional linear vibration type actuator described above is applicable. 
     As illustrated in  FIG. 1A , a vibrator  10  has a piezoelectric element  15  formed as a rectangular thin plate, an elastic member  12  fixed to the piezoelectric element  15 , and two protrusions  19  protruding from one end surface of the elastic member  12  (e.g., from the surface on the opposite side of the surface to which the piezoelectric element  15  is bonded). In the present exemplary embodiment, it is possible to provide only one protrusion or a plurality of protrusions as in the present exemplary embodiment. Further, the protrusions  19  may be provided on the surface on the side to which the piezoelectric element  15  is joined. 
     As illustrated in  FIG. 1B , each protrusion  19  has a rectangular side wall portion  14  of a hollow structure protruding with respect to the elastic member  12 , a contact portion  16  having a contact surface  17  to be brought into contact with a slider (the driven body) (not illustrated), and a connection portion  11  connecting the side wall portion  14  and the contact portion  16 . As in the present exemplary embodiment, in the case where the protrusions  19  are fixed to the elastic member  12 , there is provided a fixation portion  13  joined to the upper surface of the elastic member  12  by laser welding or the like. 
     The side wall portion  14  is continuous (i.e., continuous in a tubular fashion over the entire periphery of the protrusion  19 ), so that a predetermined rigidity in the in-XY-plane direction is secured for the protrusion  19 . A step is provided between the connection portion  11  and the contact portion  16 , with the upper surface of the connection portion  11  being lower than the contact surface  17  of the contact portion  16 . That is, the contact surface  17  protrudes farther toward the driven body side (the side opposite to the elastic member side) than the driven body side surface (the surface on the side opposite to the elastic member side) of the connection portion  11 . 
     With this structure, the slider does not come into contact with the connection portion  11 . Further, the connection portion  11  is thinner than the contact portion  16 , and, in addition, the width of the connection portion  11  is reduced through division into two by hole portions  18 , so that it is reduced in rigidity in the Z-direction and is endowed with resiliency (flexibility). In the case where a predetermined level of resiliency can be obtained solely through a reduction in its thickness, there is no need to divide the connection portion  11  into a plurality of parts by the hole portions  18 . 
     Due to the above construction, the protrusion  19  has resiliency in the Z-direction (the direction of the normal to the contact surface), so that it is possible to realize a smooth contact between the vibrator  10  and the slider. Further, even if the height of the protrusion  19  is increased for higher speed, the requisite rigidity is secured for the protrusion  19  in the X-direction, which is the driving direction of the slider, due to the continuous side wall portion  14  in its periphery, so that it is possible to transmit the drive force of the vibrator  10  efficiently to the slider. 
     Further, the protrusion  19  has at its distal end a portion having resiliency, so that the resonance frequency of the vibration mode thereof is sufficiently higher than the drive frequency of the vibrator  10 , making it possible to obtain a satisfactory actuator performance. 
     A vibrator according to a second exemplary embodiment differs from that of the first exemplary embodiment in that the protrusions are of a cylindrical configuration.  FIG. 2A  is a perspective view of a vibrator to which the second exemplary embodiment of the present invention is applicable, and  FIG. 2B  is a perspective view, partly in section, of a protrusion of the vibrator. The present exemplary embodiment is also applied to a linear vibration type actuator, and its driving principle is the same as that of the conventional linear vibration type actuator, so that the description thereof will be omitted. 
     As illustrated in  FIG. 2A , a vibrator  20  has a piezoelectric element  25 , an elastic member  22  fixed to the piezoelectric element  25 , and two protrusions  29  protruding from one end surface of the elastic member  22 . As illustrated in  FIG. 2B , each protrusion  29  has a cylindrical side wall portion  24  provided so as to protrude from the elastic member  22 , a contact portion  26  having a contact surface  27  to be brought into contact with a slider (not illustrated), and connection portions  21  connecting the side wall portion  24  and the contact portion  26 . 
     The side wall portion  24  is fixed to the elastic member  22  by laser welding or the like through the intermediation of a fixation portion  23 . Since the side wall portion  24  is continuous over the entire periphery of the protrusion  29 , a predetermined level of rigidity is secured for the protrusion  29  with respect to the in-XY-plane direction. A step is provided between the connection portion  21  and the contact portion  26 , and the upper surface of the connection portion  26  is lower than the contact surface  27 , so that the slider does not come into contact with the connection portion  21 . 
     The connection portion  21  is thinner than the contact portion  26 , and further, the connection portion  21  is divided into four by hole portions  28  to be reduced in width, so that it is reduced in rigidity in the Z-direction to be endowed with a predetermined level of resiliency. In the case where the predetermined level of resiliency can be obtained solely through a reduction in thickness, there is no need for the connection portion  21  to be divided by the hole portions  28 . 
     With this construction, the protrusion  29  exhibits resiliency in the Z-direction, so that it is possible to realize a smooth contact between the vibrator  20  and the slider. Further, if the height of the protrusion  29  is increased for higher speed, the requisite rigidity in the X-direction, which is the driving direction for the slider, is secured for the protrusion  29  due to the side wall portion  24 , so that it is possible to transmit the drive force of the vibrator  20  efficiently to the slider. 
     Further, the protrusion  29  exhibits resiliency at the distal end thereof, so that the resonance frequency in the vibration mode thereof is sufficiently higher than the drive frequency of the vibrator  20 , making it possible to obtain a satisfactory actuator performance. Further, in the present exemplary embodiment, the protrusion  29  is of a cylindrical configuration, so that it is possible to further increase the rigidity of the side wall portion  24  as compared with the first exemplary embodiment. 
     In a vibrator according to a third exemplary embodiment, the thickness of the contact portion is equal to that of the connection portion, and the contact portion is smaller in volume as compared with that in the second exemplary embodiment.  FIG. 3A  is a perspective view of a vibrator to which the third exemplary embodiment of the present invention is applicable, and  FIG. 3B  is a perspective view, partly in section, of a protrusion of the vibrator. The actuator of the present exemplary embodiment is also a linear vibration type actuator, and its driving principle is the same as that of the conventional linear vibration type actuator, so that the description thereof will be omitted. 
     As illustrated in  FIG. 3A , a vibrator  30  has a piezoelectric element  35 , an elastic member  32  to which the piezoelectric element  35  is fixed, and two protrusions  39  protruding from one end surface of the elastic member  32 . As illustrated in  FIG. 3B , each protrusion  39  has a cylindrical side wall portion  34 , a contact portion  36  having a contact surface  37  to be brought into contact with a slider (not illustrated), and a connection portion  31  connecting the side wall portion  34  and the contact portion  36 . 
     The side wall portion  34  is fixed to the elastic member  32  by laser welding or the like via a fixation portion  33 . A step is provided between the connection portion  31  and the contact portion  36 , and the upper surface of the connection portion  31  is lower than the contact surface  37 , so that the slider does not come into contact with the connection portion  31 . The connection portion  31  is divided into four by hole portions  38  to be thereby reduced in width, whereby it is reduced in rigidity in the Z-direction and endowed with a predetermined level of resiliency. 
     The step between the connection portion  31  and the contact portion  36  is formed by performing drawing on the distal end portion of the protrusion  39 . Thus, the contact portion  36  has a thickness equal to that of the connection portion  31 , and is reduced in volume as compared with the contact portion  26  of the second exemplary embodiment. Thus, it is possible to further increase the resonance frequency of the vibration mode of the protrusion  29  as compared with that of the second exemplary embodiment. 
     A vibrator according to a fourth exemplary embodiment of the present invention is a rotary vibration type actuator. A rotary vibration type actuator mainly generates through excitation a progressive wave in a vibrator to generate an elliptic movement in a protrusion of the vibrator. As for the construction and driving principle of the vibrator, a number of examples thereof have been discussed in Japanese Patent Application Laid-Open No. 2006-311790, etc., so a description thereof will be omitted. 
       FIG. 4  is a schematic diagram illustrating a vibrator to which the fourth exemplary embodiment of the present invention is applicable. It is realized by applying the protrusions  29  and  39  illustrated in  FIGS. 2A, 2B, 3A, and 3B  to the vibrator of a rotary vibration type actuator. As illustrated in  FIG. 4 , a vibrator  40  has a ring-shaped piezoelectric element  45 , an elastic member  42  to which the piezoelectric element  45  is fixed, and a large number of protrusions  49  provided on one end surface of the elastic member  42 . 
     With this construction, the protrusions  49  exhibit resiliency in the Z-direction, making it possible to realize a smooth contact between the vibrator  40  and a rotor (not illustrated) constituting a driven body. Further, if the height of the protrusions  49  is increased for higher speed, it is possible for the protrusions  49  to transmit the drive force of the vibrator  40  efficiently to the rotor. 
     In a vibrator according to a fifth embodiment of the present invention, the elastic member and the protrusions are formed of the same elastic material. Otherwise, the fifth exemplary embodiment is the same as the second exemplary embodiment, and the driving principle thereof is the same as that of the conventional linear vibration type actuator. 
       FIG. 5A  is a perspective view of a vibrator to which the fifth exemplary embodiment is applicable, and  FIG. 5B  is a perspective view, partly in section, of a protrusion thereof. As illustrated in  FIG. 5A , a vibrator  50  has a piezoelectric element  55 , an elastic member  52  to which the piezoelectric element  55  is fixed, and two protrusions  59  provided on one end surface of the elastic member  52 . 
     The elastic member  52  and the protrusions  59  are formed so as to be integrally continuous with each other. As illustrated in  FIG. 5B , each protrusion  59  has a cylindrical side wall portion  54 , a contact portion  56  having a contact surface  57  to be brought into contact with a slider (not illustrated), and a connection portion  51  connecting the side wall portion  54  and the contact portion  56 , with the connection portion  51  being divided into four by hole portions  58 . 
     A step is provided so that the upper surface of the connection portion  51  is lower than the contact surface  57 . Thus, the slider does not come into contact with the connection portion  51 . The connection portion (thin-walled portions  53 ) of the elastic member  52  with the protrusions  59  is thinner in the Z-axis direction. In the case where a predetermined level of resiliency can be obtained solely through a reduction in its thickness, there is no need to divide the connection portion  51  into a plurality of parts by the hole portions  58 .  FIG. 12A  is a perspective view of a vibrator illustrating a modification example of the fifth exemplary embodiment of the present invention, and  FIG. 12B  is a perspective view, partly in section, of a protrusion thereof. As illustrated in  FIG. 12A , a vibrator  501  has a piezoelectric element  551 , an elastic member  521  to which the piezoelectric element  551  is fixed, and two protrusions  591  provided on one end surface of the elastic member  521 . As illustrated in  FIG. 12B , each protrusion  591  has a cylindrical side wall portion  541 , a contact portion  561  having a contact surface  571  to be brought into contact with a slider (not illustrated), and a connection portion  511  connecting the side wall portion  541  and the contact portion  561 . The connection portion (thin-walled portions  531 ) of the elastic member  521  with the protrusions  591  is thinner in the Z-axis direction. With this configuration, the protrusion  591  can have higher rigidity in-XY-plane direction, so that higher efficiency can be obtained. Further, the resonance frequency of the vibration mode, in which a connection portion  511  provided at a distal end of the protrusion  591  and having resiliency vibrates, becomes higher, thereby enabling unnecessary vibrations to be restrained. 
     Next, a method of manufacturing the elastic member  52  and the protrusions  59  will be described.  FIG. 6  illustrates how press molding is performed on an elastic plate material to shape it into a final configuration. In the following, the steps involved will be described. 
     In a first step, two hollow protrusions (which later constitute the protrusions of a vibrator) are formed by performing drawing on a metal plate material  52   a  such as a stainless steel plate illustrated in  FIG. 6A , which constitutes the material of the elastic member. In order that the plate material  52   a  may not be cracked, it is advisable to perform the drawing in a plurality of steps. 
       FIG. 6B  illustrates a midway step of the drawing operation, in which there are formed protrusions  59   b  each composed of a continuous cylindrical side wall portion  54   b  and a distal end portion ( 51   b ,  56   b ) later constituting the connection portion and the contact portion. To provide the protrusions  59   b  through drawing, the periphery of each side wall portion  54   b  is squeezed into a thin-walled portion  53   b , with the portion of the material corresponding to this reduction in thickness being caused to flow to the side wall portion  54   b . Usually, the thickness of the side wall portion  54   b  is smaller than that of the plate material  52   a  ( 52   b ). 
       FIG. 6C  illustrates the final stage of the drawing process, in which there are formed protrusions  59   c  each composed of a continuous cylindrical side wall portion  54   c , a connection portion  51   c , and a contact portion  56   c . Along with the drawing, squeezing is performed on the outer peripheral portion of the distal end portion  51   b  illustrated in  FIG. 6B  in a direction opposite to the direction in which the protrusion protrudes, whereby there is provided a thin-walled portion (connection portion  51   c ), forming a step between itself and the contact portion  56   c  at the center of the distal end portion. 
     As a result, a slider (not illustrated) to be brought into contact with the contact surface  57   c  does not come into contact with the connection portion  51   c . Further, due to its small thickness, the connection portion  51   c  exhibits resiliency. As illustrated in  FIG. 3B , the step between the contact portion  56   c  and the connection portion  51   c  may also be provided by further performing drawing on the distal end portion  51   b  to cause the central portion of the distal end portion  51   b  constituting the contact portion to protrude farther than the outer periphery of the distal end portion  51   b.    
     The second step consists of a punching process for endowing the connection portion  51   c  with a predetermined level of resiliency, and  FIGS. 6D and 6E  illustrate how the punching is performed. In the present exemplary embodiment, the connection portion is divided into four to reduce the width of the connection portion, so that performing punching at a time may involve cracking or deformation. In view of this, the punching is performed in two stages. 
     As illustrated in  FIG. 6D , punching is performed on two opposing portions of the four portions to forma hole portion  58   d . After this, as illustrated in  FIG. 6E , punching is performed on the two remaining portions to forma plurality of connection portions  51   e  having a predetermined level of resiliency due to hole portions  58   e . In the case where the predetermined level of resiliency can be attained without having to divide the connection portion, this step is unnecessary. 
     The third and final step is a contour punching step for shaping the elastic member  52   e  of  FIG. 6E  into the shape of a vibrator functioning as a vibration type actuator.  FIG. 6F  illustrates the ultimate shape of the elastic member. As illustrated in  FIG. 5A , the elastic member  52   f  may be shaped into a rectangular elastic member shape in the XY-plane. As illustrated in  FIG. 6F , in the case where support portions  521  for fixing the elastic member to a pedestal (not illustrated) are provided on side surfaces of the elastic member, the plate material is punched into a shape consisting of the elastic member and support portions. 
     In the present exemplary embodiment, the “shape of the vibrator” refers to the shape of the elastic member within the plane (XY-plane) in which the piezoelectric element is joined, or the shape consisting of the elastic member and the support portions within the plane in which the piezoelectric element is joined. As illustrated in  FIG. 6F , the support portions  521  are provided at positions where they do not hinder the vibration of the elastic member  52   f , for example, at both longitudinal ends of the elastic member, and the shape of the support portions  521  may be one that does not hinder the vibration of the elastic member  52   f.    
     As described above, by the integral presswork illustrated with regard to the first through third steps, there is formed the elastic member  52   f , which is integrated with the protrusions  59   f . And, by joining the piezoelectric element to the elastic member  52   f , the vibrator is formed. 
     In a vibrator according to a sixth exemplary embodiment, the connection portion reaches not only the distal end of the protrusion but also to the side surface thereof. Otherwise, it is of the same construction as the fifth exemplary embodiment, and its driving principle is the same as that of the conventional linear vibration actuator. 
       FIG. 7A  is a perspective view of a vibrator according to the sixth exemplary embodiment, and  FIG. 7B  is a perspective view, partly in section, of a protrusion thereof. As illustrated in  FIG. 7A , a vibrator  60  has a piezoelectric element  65 , an elastic member  62  to which the piezoelectric member  62  is fixed, and two protrusions  69  provided on one end surface of the elastic member  62 . 
     The elastic member  62  and the protrusions  69  are formed integrally and continuously with each other. As illustrated in  FIG. 7B , each protrusion  69  is composed of a cylindrical side wall portion  64 , a contact portion  66  having a contact surface  67  to be brought into contact with a slider (not illustrated), and a connection portion  61  connecting the side wall portion  64  and the contact portion  66 . 
     A step is provided so that the upper surface of the connection portion  61  is lower than the contact surface  67 , thereby preventing the slider from coming into contact with the connection portion  61 . The connection portion  61  is reduced in thickness and is divided into a plurality of portions by hole portions  68 , whereby it is reduced in rigidity in the Z-direction and is endowed with a predetermined level of resiliency. 
     In the present exemplary embodiment, the continuous side wall portion  64  is solely formed at the root of the protrusion  69 , and the hole portions  68  dividing the connection portion  61  reach not only the distal end of the protrusion but also the side surface thereof. Accordingly, the connection portion  61  exhibits some resiliency not only in the Z-direction but also in the in-XY-plane direction. This is effective in smoothing the contact with the slider in the case where the in-XY-plane component of the vibration of the vibrator  60  is large. Further, at the connection portions (thin-walled portions  63 ) thereof connected with the protrusions  69 , the elastic member  62  is reduced in thickness in the Z-direction. 
     Next, a method of manufacturing the elastic member  62  and the protrusions  69  will be described.  FIGS. 8A through 8E  illustrate the steps in which press molding is performed on the plate material of the elastic member to shape it into the ultimate shape. In the following, the steps will be described. In the first step, punching is performed on a plate material formed of a metal such as stainless steel constituting the elastic member  62   a  illustrated in  FIG. 8A , whereby there is prepared a plate material  62   b  having a plurality of hole portions  68   b  as illustrated in  FIG. 8B . 
     In the second step, drawing is performed on the plate material  62   b  illustrated in  FIG. 8B  to thereby form two protrusions (which are to constitute the protrusions of the vibrator). In order that the plate material  62   b  may not be cracked, the drawing is performed in a plurality of stages.  FIG. 8C  illustrates a mid stage thereof, in which there are formed cylindrical continuous side wall portions  64   c  and distal end portions (distal end portion centers  66   c  and outer peripheral portions  61   c  of the distal end portions) which later constitute the contact portions and the connection portions. 
     Each distal end portion outer peripheral portion  61   c , which later constitutes a connection portion, is divided into a plurality of portions by hole portions  68   c  previously formed in the first step. In order to provide protrusions  69   c  through drawing, the periphery of each side wall portion  64   c  is squeezed into a thin-walled portion  63   c , and the portion of the material corresponding to the reduction in thickness through the squeezing is caused to flow to the side wall portion  64   c . Usually, the thickness of the side wall portion  64   c  is smaller than the thickness of the plate material  62   a  ( 62   c ). 
       FIG. 8D  illustrates the final stage of the drawing. As a result of this drawing, there are formed protrusions  69   d  each composed of a cylindrical continuous side wall portion  64   d , a connection portion  61   d  divided into a plurality of portions by hole portions  68   d , and a contact portion  66   d . Along with the drawing, squeezing is performed on the connection portion  61   d , whereby its thickness is reduced, by forming a step between the connection portion  61   d  and the contact portion  66   d.    
     As a result, the contact surface  67   d  is higher than the upper surface of the connection portion  61   d , and the slider (not illustrated) does not come into contact with the connection portion  61   d . Further, the connection portion  61   d  has a small wall thickness and is divided into a plurality of portions, so that it exhibits a predetermined level of resiliency in the Z-direction and, at the same time, since the side surface is also partly divided, it exhibits some resiliency also in the Z-direction. The step between the contact portion  66   d  and the connection portion  61   d  may be provided by further performing drawing on the distal ends of the protrusions as illustrated in  FIG. 3B . 
     As in the fifth exemplary embodiment, in the third and final step, there is performed contour punching to shape the elastic member  62   d  illustrated in  FIG. 8D  into the shape of a vibrator functioning as a vibration type actuator.  FIG. 8E  illustrates the ultimate shape of the elastic member. As illustrated in  FIG. 7A , the elastic member  62   e  may be formed through punching into the shape of a rectangular elastic member in the XY-plane, and in the case where support portions  621  are provided as illustrated in  FIG. 8F , punching is performed on the material into the shape of a vibrator composed of a rectangular elastic member and support portions. 
     As described above, by the first through third steps of integral presswork, there is formed an elastic member  62   e  integrated with the protrusions  69   e . And, by joining the piezoelectric element to the elastic member  62   e , the vibrator is formed. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.