Patent Application
20150158184
1. Technical Field
The present invention relates to a piezoelectric motor, a robot hand, a robot, a finger assist apparatus, an electronic component conveying apparatus, an electronic component inspecting apparatus, a liquid feed pump, a printing apparatus, an electronic timepiece, and a projecting apparatus.
2. Related Art
A piezoelectric motor configured to drive an object by vibrating a vibrating body including a piezoelectric material is known. The piezoelectric motor is characterized by being capable of obtaining a large drive force although being smaller than an electromagnetic motor using an electromagnetic force, and being capable of positioning the object at a high resolution capability.
The piezoelectric motor is operated in the following principle. First of all, a voltage is applied to a vibrating body to cause the vibrating body to generate a predetermined vibration. Then, an end portion of the vibrating body moves along a specific trajectory, and hence an object may be driven frictionally by bringing the end portion into abutment with the object adequately. From the operation principle as described above, if the vibrating body moves by receiving a reaction force from the object, a sufficient drive force cannot be transmitted to the object. Therefore, the vibrating body needs to be supported so as not to move even though a reaction force is applied. Accordingly, JP-A-8-237971 proposes a supporting structure including a plurality of coupling portions extending from a side surface in a bending direction of the vibrating body performing a bending vibration and configured to couple the vibrating body with a fixing portion, and the plurality of coupling portions extending in the same direction with respect to the vibrating body are connected by a supporting portion.
However, with the vibrating body supporting structure as described in JP-A-8-237971, there is a problem that driving characteristics of the piezoelectric motor are affected from the following reasons. First of all, there is a case where a resonance may occur unintentionally in the supporting portion by the vibration of the vibrating body transmitted to the supporting portion via the coupling portions. The resonance disturbs the original vibration of the vibrating body, and hence the trajectory of the movement of the end portion is disordered. Accordingly, modes of abutment such as a strength of abutment of the end portion of the vibrating body with the object and a range (stroke) of abutment of the end portion with the object on the trajectory of movement vary. Consequently, a predetermined drive force cannot be transmitted to the object, and hence the driving characteristics of the piezoelectric motor such as an efficiency of driving of the object and positioning accuracy of the object may be lowered.
An advantage of some aspects of the invention is to provide a technology which is capable of supporting a vibrating body without affecting driving characteristics of a piezoelectric motor.
A piezoelectric motor according to an aspect of the invention employs the following configuration. That is, an aspect of the invention is directed to a piezoelectric motor including: a vibrating body capable of generating a bending vibration; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
The term “rigidity” used in the aspect of the invention means a “nature that resists deformation caused by an external force when the external force is applied”. Examples of the term “the rigidity of the supporting portion is high” include that the amount of deflection when the supporting portion is pressed is small, that the amount of bending when the supporting portion is bent is small, and the amount of twisting when the supporting portion is twisted is small.
In this configuration, even though a vibration (vibration allowed at the joint portion) generated by the vibrating body is transmitted to the supporting portion, the vibration is suppressed (is not allowed) at the supporting portion having rigidity higher than that of the joint portion. By restraining the unintentional occurrence of the resonance in the supporting portion in this manner, the original vibration of the vibrating body is not disturbed, and the end portion of the vibrating body moves along a specific trajectory, so that a predetermined drive force may be transmitted to the object. Consequently, the vibrating body can be supported while maintaining driving characteristics of the piezoelectric motor.
The piezoelectric motor according to the aspect of the invention described above may be provided with a reinforcing member configured to enhance the rigidity of the supporting portion.
In this configuration, since the rigidity of the supporting portion becomes higher than the rigidity of the joint portion and hence vibration is restrained, so that unintentional occurrence of the resonance in the supporting portion may be restrained.
In the piezoelectric motor provided with the reinforcing member according to the aspect of the invention described above, the reinforcing member may contain a vibration damping material.
In this configuration, since the vibration damping material disperses vibration energy absorbed thereby as heat and sound to damp the vibration transmitted to the supporting portion, unintentional occurrence of the resonance in the supporting portion may be restrained more reliably.
In the piezoelectric motor according to the aspect of the invention described above, the supporting portion may include a bent portion bent along a segment intersecting a direction of bending of the vibrating body.
In this configuration, in a portion of the supporting portion provided with the bent portion, the rigidity of the supporting portion becomes higher than that of the joint portion and hence the vibration is restrained, so that unintentional occurrence of the resonance in the supporting portion may be restrained.
In the piezoelectric motor according to the aspect of the invention described above, the supporting portion may be formed to have a thickness larger than that of the joint portion.
In this configuration, the rigidity of the supporting portion becomes higher than the rigidity of the joint portion and hence vibration is restrained, so that unintentional occurrence of the resonance in the supporting portion may be restrained.
In the piezoelectric motor according to the aspect of the invention described above, the supporting portion may be formed of a material having rigidity higher than that of the joint portion.
In this configuration, the rigidity of the supporting portion becomes higher than the rigidity of the joint portion and hence vibration is restrained, so that unintentional occurrence of the resonance in the supporting portion may be restrained.
In the piezoelectric motor according to the aspect of the invention as described above, the joint portion, the supporting portion, and the coupling portions may be formed integrally from a single plate member.
In this configuration, a process of joining these members (fastening by a joint screw, adhesion with an adhesive agent, point welding, and so on) may be omitted, so that manufacture of the piezoelectric motor may be facilitated in comparison with the case where these members are provided separately. In addition, since the member such as the joint screw is no longer necessary, reduction of manufacturing cost of the piezoelectric motor is achieved.
In the piezoelectric motor including the joint portion, the supporting portion, and the coupling portions formed integrally according to the aspect of the invention described above, a leaf spring configured to bias the vibrating body toward the object to be driven by the piezoelectric motor may be formed by bending a single plate member to form the joint portion, the supporting portion, and the coupling portions integrally.
In this manner, by forming the leaf spring integrally with the joint portion, the supporting portion, and the coupling portions, facilitating the manufacture of the piezoelectric motor by omitting a process of joining the leaf spring or reducing the manufacturing cost without necessity of the member such as a joint screw is achieved.
In the piezoelectric motor including the joint portion, the supporting portion, the coupling portions, and the leaf spring formed integrally according to the aspect of the invention described above, a fixing portion configured to fix the piezoelectric motor at a predetermined position may be formed integrally with the joint portion, the supporting portion, the coupling portions, and the leaf spring by bending a single plate member integrally.
In this manner, by forming the fixing portion integrally with the joint portion, the supporting portion, the coupling portions, and the leaf spring, facilitating the manufacture of the piezoelectric motor by omitting a process of joining the fixing portion or reducing the manufacturing cost without necessity of the member such as the joint screw is achieved.
In the piezoelectric motor according to the aspect of the invention as described above, a front node portion closer to the object, a rear node portion farther from the object, and a middle node portion between the front node portion and the rear node portion are provided on the vibrating body as node portions having an amplitude of the bending vibration smaller than that of an end portion on a side abutting against the object that the piezoelectric motor drives, and the coupling portions may be provided at selected two or more of the front node portion, the middle node portion, and the rear node portion.
With the provision of the coupling portions on the node portions of the vibrating body in this manner, vibrations to be transmitted to the supporting portion via the coupling portions may be reduced to restrain the unintentional occurrence of resonance in the supporting portion in comparison with the case where the coupling members are provided at portions different from the node portions (antinode portions having an amplitude of the bending vibration equivalent to the end portion on the side of abutting against the object). Since the transmission (release) of the vibration to an outer portion (the coupling portions or the supporting portion) of the vibrating body may be restrained, the object may be driven efficiently by reducing a loss of driving energy.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as a robot hand configured to be capable of grasping an object with a finger portion, including: a base member having the finger portion extending upright so as to be movable; a movable portion interlocked with a movement of the finger portion or a rotation of joints of the finger portion with respect to the base member; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the movable portion and drive the movable portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the robot hand according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the movable portion, and accuracy of gripping the object with the finger portion can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as a robot including: an arm portion provided with a rotatable joint portion; a hand portion provided on the arm portion; a body portion provided with the arm portion; a movable portion interlocked with a rotation of the joint portion; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the movable portion and drive the movable portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the robot according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the movable portion, and accuracy of the movement of the robot can be enhanced. The hand portion may be a hand portion configured to perform, for example, an operation for gripping the object, a screw-tightening operation for tightening a screw, a coating operation, and a welding operation.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as a finger assist apparatus worn on a finger and configured to assist a bending or stretching movement of the finger, including: a first member to be worn on the finger; a second member worn on the finger and coupled to the first member so as to be rotatable in a direction in which the finger is bent; a movable portion interlocked with the rotation of the second member; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the movable portion and drive the movable portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined, a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the finger assist apparatus according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the movable portion, and accuracy of assisting the movement of the finger bending or stretching can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as an electronic component conveying apparatus provided with a gripping portion configured to grip an electronic component, including: a movable portion interlocked with the movement of the gripping portion that grips the electronic component; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the movable portion and drive the movable portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the electronic component conveying apparatus according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the movable portion, and accuracy of conveying the electronic component can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention construed as an electronic component inspection apparatus including: a gripping portion configured to grip an electronic component; an inspecting portion configured to inspect the electronic component; a movable portion interlocked with the movement of the gripping portion that grips the electronic component; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the movable portion and drive the movable portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the electronic component inspection apparatus according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the movable portion, and accuracy of inspecting the electronic component can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be configured as a liquid feed pump including: a tube which allows liquid to flow therethrough; a closing portion configured to abut against the tube and close the tube; a moving portion configured to move the closing portion; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the moving portion and drive the moving portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the liquid feed pump according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the moving portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the moving portion, and accuracy of feeding liquid in the tube can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as a printing apparatus including: a printhead configured to print an image on a medium; a moving portion configured to move the printhead; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the moving portion and drive the moving portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the printing apparatus according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the moving portion, and accuracy of printing an image can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as an electronic timepiece including: a rotatable rotary disc coaxially provided with a gear; a gear train including a plurality of teeth; a hand connected to the gear train and configured to point out time of the day; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the rotary disc and drive the rotary disc by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the electronic timepiece according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the rotary disc without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the rotary disc, and accuracy of the movement of the electronic timepiece can be enhanced.
The aspect of the invention may be construed as the following configuration. That is, another aspect of the invention can be construed as a projecting apparatus including: a light source configured to generate light; a projecting portion including an optical lens and configured to project the light; a moving portion configured to move the optical lens; a vibrating body capable of generating a bending vibration; an abutting portion configured to abut against the moving portion and drive the moving portion by transmitting the vibration of the vibrating body; a joint portion to which the vibrating body is joined; a supporting portion disposed in parallel to the joint portion and configured to support the vibrating body and the joint portion; and a plurality of coupling portions configured to couple the joint portion and the supporting portion, wherein the supporting portion has rigidity higher than that of the joint portion.
With the projecting apparatus according to the aspect of the invention configured in this manner, since the support of the vibrating body may be enhanced to prevent the vibrating body from being moved by a reaction force that the abutting portion receives from the movable portion without affecting the vibration of the vibrating body, the vibration of the vibrating body is adequately transmitted to the moving portion, and accuracy of adjusting the projecting state of light by the optical lens can be enhanced.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
The vibrating body 110 has a parallelepiped shape, and is provided with a projecting portion 122 configured to abut against an object to be driven by the piezoelectric motor 100 on an end surface in the longitudinal direction. A detailed structure of the vibrating body 110 will be described with reference to other drawings. The longitudinal direction of the vibrating body 110 is referred below to as an X-direction. In the drawing, the short direction of the vibrating body 110 orthogonal to the X-direction is referred to as a Y-direction, and a thickness direction of the vibrating body 110 orthogonal to the X-direction and the Y-direction is referred to as a Z-direction.
The supporting portions 128 are provided on both sides in parallel in the short direction (Y-direction) of the vibrating body 110, and are coupled by the vibrating body 110 and a plurality of coupling portions (a pair of front coupling portions 124 and a pair of rear coupling portions 125). The front coupling portions 124 and the rear coupling portion 125 are provided apart from each other in the longitudinal direction (X-direction) of the vibrating body 110. The front coupling portions 124 couple a side of the vibrating body 110 provided with the projecting portion 122, and the rear coupling portions 125 couple a side opposite to the side of the vibrating body 110 provided with the projecting portion 122. The supporting portion 128 of this example is a rectangular flat plate formed integrally with the front coupling portions 124 and the rear coupling portions 125 as illustrated in the drawing. Then, a parallelepiped shaped reinforcing member 140 for reinforcing the supporting portions 128 (for enhancing the rigidity) is provided so as to be in tight contact with a lower surface of the supporting portions 128.
The two leaf springs (the front leaf spring 150 and the rear leaf spring 160) are arranged so as to be apart from each other in the longitudinal direction (X-direction) of the vibrating body 110. A pair of the front leaf springs 150 provided on the side of the vibrating body 110 where the projecting portion is provided are formed by bending from a fixing portion 152, which is to be fixed at a position where the piezoelectric motor 100 is installed (an X-Y plane) and with fixing screws 154, in the Z-direction (upward direction in the drawing) so as to interpose the vibrating body 110 therebetween. The front leaf spring 150 faces the X-direction, and may be deflected in the X-direction. A distal end side (the side opposite to the fixing portion 152) of the front leaf spring 150 is bent in the X-direction (inner side in the drawing) to form a base portion 156. End portions of the supporting portions 128 on the front coupling portions 124 side are joined to the base portion 156 by joint screws 158. A method of joining the supporting portions 128 and the base portion 156 may be adhesion or welding.
The rear leaf spring 160 provided on the side opposite to the side where the projecting portion 122 of the vibrating body 110 is provided is formed in plane symmetry with the front leaf spring 150 with respect to a Y-Z plane. In other words, a pair of the rear leaf springs 160 are provided so as to interpose the vibrating body 110 therebetween by being bent from a fixing portion 162, which is fixed with a fixing screw 164, in the Z-direction (upward direction in the drawing) and may be deflected in the X-direction. A distal end side (the side opposite to the fixing portion 162) of the rear leaf spring 160 is bent in the X-direction (toward the near side in the drawing) to form a base portion 166, and end portions of the supporting portions 128 on the rear coupling portions 125 side are joined to the base portion 166 with joint screws 168.
The metallic shim plate 120 has a function not only to reinforce the piezoelectric elements (front piezoelectric element 130 and back piezoelectric element 131), but also as a common electrode for applying a voltage to the front piezoelectric element 130 and the back piezoelectric element 131 and grounded. As described above, the projecting portion 122 configured to abut against the object is provided at the end portion of the vibrating body 110 in the longitudinal direction (X-direction), and the projecting portion 122 is formed integrally with the shim plate 120 by punching a single plate member. The shim plate 120 of this example corresponds to the “joint portion” according to the invention.
As described above, the supporting portions 128 are provided on the both sides in parallel in the Y-direction of the vibrating body 110, and the vibrating body 110 and the supporting portions 128 are coupled by a pair the of front coupling portions 124 and a pair of the rear coupling portions 125. In the piezoelectric motor 100 of this example, a pair of the front coupling portions 124 and the rear coupling portions 125 and a set of the supporting portions 128 and the shim plate 120 are formed integrally by punching a single metallic flat plate. In this configuration, a process of joining these members (fastening by a joint screw, adhesion with an adhesive agent, point welding, and so on) may be omitted, so that manufacture of the piezoelectric motor 100 may become facilitated in comparison with the case where these members are formed separately. In addition, since the member such as the joint screw is no longer necessary, reduction of manufacturing cost of the piezoelectric motor 100 is achieved.
First of all, as publicly known, the piezoelectric elements (front piezoelectric element 130 and back piezoelectric elements 131) including the piezoelectric material has a nature of expanding when a positive voltage is applied. Therefore, as illustrated in
As illustrated in
By selecting a physical property of the front piezoelectric element 130 and dimensions of the front piezoelectric element 130 (width W, length L, and thickness T) adequately, resonance of the bending vibration may be induced and, simultaneously, resonance of an “expansion and contraction vibration” may also be induced. Consequently, in the case where a voltage is applied to the pair of the front electrode 132a and the front electrode 132d in a mode illustrated in
The piezoelectric motor 100 drives the object by using the oval movement of the vibrating body 110 as described above. In other words, the piezoelectric motor causes the oval movement in a state in which the projecting portion 122 of the vibrating body 110 is pressed against the object. Then, the projecting portion 122 repeats an operation of moving from the left to the right (or from the right to the left) in a state in which the vibrating body 110 is pressed against the object when the vibrating body 110 expands, and restoring the original state in a state of being apart from the object when the vibrating body 110 contracts. Consequently, the object is driven in one direction by a frictional force received from the projecting portion 122.
Now, the vibrating body 110 which generates the bending vibration by the application of the voltage as described above does not vibrate uniformly as a whole, but has portions (node portions) having a smaller amplitude of the bending vibration in comparison with the distal end portion where the projecting portion 122 is provided.
On both sides of the front node portion 116a in the Y-direction, which is located on the side closer to the projecting portion 122 from among the node portions 116 at three positions, the pair of front coupling portions 124 described above are provided, and on both sides of the rear node portion 116c located on the side far from the projecting portion 122 in the Y-direction, the pair of rear coupling portions 125 described above are provided (See
In this manner, the projecting portion 122 providing the rotor W with a drive force receives a reaction force having the same magnitude as, and in a direction opposite to, the drive force from the rotor W. If the vibrating body 110 is moved by the reaction force, a sufficient drive force cannot be transmitted to the rotor W. Therefore, in the piezoelectric motor 100 of this example, the front coupling portions 124 and the rear coupling portions 125 are provided to couple the vibrating body 110 with the supporting portions 128 so that the vibrating body 110 is prevented from being moved by the reaction force.
First of all, by providing the front coupling portions 124 on the front node portion 116a of the vibrating body 110, the side closer to the projecting portion 122, which receives the reaction force, is coupled to the supporting portions 128 to resist the reaction force. However, only with the coupling between the front node portion 116a and the supporting portions 128, the projecting portion 122 moves away from the rotor W while swinging the side of the vibrating body 110 opposite to the projecting portion 122 (rear side) around about the front node portion 116a as a supporting point, so that a drive stroke (a range in which the projecting portion 122 transmits the drive force to the rotor W on an oval trajectory) can hardly be obtained. Therefore, by providing the rear coupling portions 125 on the rear node portion 116c of the vibrating body 110 to couple the side far from the projecting portion 122 with the supporting portions 128, the swinging-around movement of the rear side of the vibrating body 110 may be restrained, so that a significant drive stroke may be secured against the reaction force.
Furthermore, in the piezoelectric motor 100 of this example, the front coupling portions 124 and the rear coupling portions 125 are connected by the supporting portions 128. Accordingly, in comparison with the case where the supporting portions 128 are not provided, the reaction force received by the projecting portion 122 may be transmitted not only to the front leaf spring 150, but also to the rear leaf spring 160 via the supporting portions 128 to resist the reaction force. Therefore, the support of the vibrating body 110 to prevent the vibrating body 110 from moving due to the reaction force can be further enhanced. However, if the front coupling portions 124 and the rear coupling portions 125 are connected by the supporting portions 128, driving characteristics of the piezoelectric motor 100 may change.
Therefore, in the piezoelectric motor 100 of this example, as described with reference to
The term “rigidity” of this example means “nature that resists deformation caused by an external force applied”. As a method of evaluating the fact that “the supporting portions 128 have rigidity higher than that of the shim plate 120”, the following method may be exemplified. For example, when the amounts of deflection of the supporting portions 128 and the shim plate 120 are compared by pressing with an application of the same magnitude of force to center portions of them in the X-direction from the Z direction, it is accepted if the amount of deflection of the supporting portions 128 is smaller than that of the shim plate 120. Alternatively, when the amounts of bending of the supporting portions 128 and the shim plate 120 are compared by fixing at one ends of them in the X-direction and the same magnitude of force is applied and bend the other ends from the Z direction, it is accepted if the amount of bending of the supporting portions 128 is smaller than that of the shim plate 120. Alternatively, when the amounts of twisting of the supporting portions 128 and the shim plate 120 are compared by fixing at one ends of them in the X-direction and twisting the other ends with the same magnitude of force about in the X-direction as an axis, it is accepted if the amount of twisting of the supporting portions 128 is smaller than that of the shim plate 120. These comparative evaluations are performed before joining the piezoelectric elements 130 and 131 to the shim plate 120, whereby an evaluation with higher degree of accuracy is achieved.
In the piezoelectric motor 100 of this example, the front coupling portions 124 and the rear coupling portions 125 are provided at the node portions 116 of the vibrating body 110 generating less vibration as described above. Therefore, in comparison with the case where the coupling portions 124 and 125 are provided at portions other than the node portions 116 (such as the antinode portions 114), unintentional occurrence of the resonance in the supporting portion 128 in this manner may be restrained by reducing the vibration transmitted to the supporting portions 128 via the coupling portions 124 and 125.
The material to be used for the reinforcing member 140 may include a material having not only a high rigidity, but also a small coefficient of vibration (so-called a vibration damping material). In this configuration, by using the vibration damping material for the reinforcing member 140, the vibration damping material disperses vibration energy absorbed thereby as heat and sound to damp the vibration transmitted to the supporting portion 128, and hence unintended occurrence of the resonance in the supporting portion 128 may be restrained further reliably.
Modifications of the piezoelectric motor 100 of this example described above will be described below. In the description of the modifications, components which are the same as those of the example described above are denoted by the same reference signs as the example, whereby the detailed description will be omitted.
In this manner, by forming the shim plate 120, the coupling portions 124 and 125, the supporting portions 128, the leaf springs 150 and 160, and the fixing portions 152 and 162 integrally by punching and bending a single metallic flat plate, a process of joining these members with each other is omitted in comparison with the case where these members are formed separately, so that the manufacture of the piezoelectric motor 100 is facilitated. In addition, since the member such as the joint screw is no longer necessary, reduction of manufacturing cost of the piezoelectric motor 100 is achieved.
In this manner, by bending both sides of the supporting portions 128 in the Y-direction, rigidity higher than that of the shim plate 120 is ensured at the portions of the supporting portions 128 provided with the bent portions 129. Accordingly, in the same manner as the example described above, even though the vibration generated in the vibrating body 110 (shim plate 120) is transmitted to the supporting portions 128, the vibration may be restrained in the supporting portions 128. Therefore, unintended occurrence of resonance in the supporting portions 128 is retrained, so that the driving characteristics of the piezoelectric motor 100 may be maintained. The bent portion 129 may be formed integrally with the shim plate 120, the coupling portions 124 and 125, and the supporting portions 128 from a single metallic flat plate, the rigidity of the supporting portions 128 may be enhanced without preparing an additional member (reinforcing member 140).
The bending work to be performed on the supporting portions 128 is not limited to a mode of bending at a right angle with respect to the supporting portions 128 as illustrated in
In this manner, by forming the supporting portions 128 to be thicker than the shim plate 120, the rigidity of the supporting portions 128 may be set to be higher than that of the shim plate 120. Accordingly, in the same manner as the example described above, the vibration transmitted from the vibrating body 110 (shim plate 120) may be restrained in the supporting portions 128. Therefore, unintended occurrence of resonance in the supporting portions 128 is retrained, so that the driving characteristics of the piezoelectric motor 100 may be maintained.
In the third modification described above, the rigidity is enhanced by forming the supporting portions 128 to be thicker than the shim plate 120. However, the supporting portions 128 may be formed of a material having rigidity higher than that of the shim plate 120. The material used for the supporting portions 128 may include the vibration damping material in addition to a high rigidity. By using the vibration damping material, the vibration transmitted to the supporting portions 128 is damped, and hence unintended occurrence of resonance may be restrained further reliably.
In the above-described embodiment, the coupling portions 124 and 125 are provided at the front node portion 116a and the rear node portion 116c from among the three node portions 116 of the vibrating body 110 where the amplitude of the bending vibration is small. However, the positions where the coupling portions are to be provided are not limited thereto, and two or more positions may be selected from among the three node portions 116.
In the example and the modifications described above, pairs of the coupling portions 124, 125 and 126 are provided on the both sides of the vibrating body 110 in the Y-direction. However, the coupling portions may be provided only on one side. Accordingly, even when a space for installing the piezoelectric motor 100 is limited, the vibrating body 110 may be supported by coupling the supporting portions 128 to one side of the vibrating body 110.
In the above-described example, the positions for providing the coupling portions are in a symmetric fashion on the both sides of the vibrating body 110 in the Y-direction. However, the coupling portions may be provided in an asymmetric fashion.
In the vibrating body 110 of the sixth modification, the rear side portion on one side where the coupling portions 124 and 126 are provided at the front node portion 116a and the middle node portion 116b and the front side portion on the other side where the coupling portions 126 and 125 are provided at the middle node portion 116b and the rear node portion 116c (hatched portions in the drawing) are not constrained by the coupling portions 124, 125 and 126, so that large vibration is allowed. Therefore, by applying a voltage to these portions, the trajectory of the oval movement in one direction (leftward turn in the illustrated example) of the projecting portion 122 may be larger than the trajectory of the oval movement in the other direction. By setting the object adequately so as to match the oval movement having a larger trajectory, a large drive stroke may be ensured. In this manner, by providing the coupling portions at the positions in a asymmetry fashion on the both sides of the vibrating body 110 in the Y-direction and specifying the driving direction of the object to one direction, the object can be driven efficiently.
The piezoelectric motor 100 of the above-described example or the piezoelectric motor 100 of the modifications are capable of enhancing the support of the vibrating body 110 without adversely affecting the driving characteristics of the piezoelectric motor 100. Therefore, the piezoelectric motor 100 may be integrated suitably as a driving unit for the apparatus described below.
As illustrated in
a disc-shaped rotor 334 configured to rotate about an axis different from that of the output member 330, a spur gear 336 rotating about the same axis as the rotor 334, and the piezoelectric motor 100 configured to rotate the rotor 334 are provided between the two frame plate 324 and 326. Teeth (not illustrated) engaging the spur gear 336 are formed on an outer periphery of the semi-circular portion of the output member 330, and when the rotor 334 rotates, the rotation is transmitted to the output member 330 at a speed reduced at a predetermined ratio via the spur gear 336, whereby the output member 330 rotates.
The piezoelectric motor 100 is fixed to the first frame plate 324 in a state in which the projecting portion 122 is pressed against an outer peripheral surface of the rotor 334. Therefore, for example, when the piezoelectric motor 100 is driven and the rotor 334 is rotated clockwise on the drawing, the second unit 320 rotates clockwise with respect to the first unit 310 coupled to the output member 330 as indicated by a hollow arrow in the drawing (the first unit 310 rotates counterclockwise with respect to the second unit 320) and is bent. In contrast, when the rotor 334 is rotated counterclockwise, the second unit 320 rotates counterclockwise with respect to the first unit 310 (the first unit 310 rotates clockwise with respect to the second unit 320), and is expanded. In this manner, in the finger assist apparatus 300, the second unit 320 can be bent or stretched with respect to the first unit 310, so that bending and stretching of the second joint of the forefinger 10 is assisted.
The finger assist apparatus 300 in this configuration is capable of assisting persons having a paralyzed finger due to diseases such as cerebral stroke or accident to make his or her finger bend or stretch, or ages persons who has weakened hand grip due to the ages by being worn on a finger. By putting the finger assist apparatus 300 on the finger of the person having a paralyzed finger, it is effective for rehabilitation especially of the action of stretching the finger.
The supporting base 430 is provided with a Y stage 432 so as to be movable in a direction parallel to the upstream stage 412u and the downstream stage 412d of the base block 410 (Y-direction), and an arm portion 434 extends from the Y stage 432 in a direction toward the base block 410 (X-direction). An X stage 436 is provided so as to be movable in the X-direction on a side surface of the arm portion 434. The X stage 436 includes an image pickup camera 438, and a gripping device 450 having a Z stage movable in a vertical direction (Z-direction) integrated therein. A gripping portion 452 configured to grip the electronic component 1 is provided at a distal end of the gripping device 450. In addition, a control device 418 configured to control the entire operation of the electronic component inspecting apparatus 400 is provided on a front side of the base block 410. In this example, the Y stage 432 provided on the supporting base 430, the arm portion 434, the X stage 436, and the gripping device 450 corresponds to “electronic component conveying apparatus” according to the invention.
The electronic component inspecting apparatus 400 having the configuration as described above performs the inspection of the electronic component 1 in the following manner. First of all, the electronic component 1 as the object of inspection is placed on the upstream stage 412u and moves to a position near the inspection bed 416. Subsequently, the Y stage 432 and the X stage 436 are moved to move the gripping device 450 to a position right above the electronic component 1 placed on the upstream stage 412u. At this time, the position of the electronic component 1 may be confirmed by using the image pickup camera 438. Subsequently, when the gripping device 450 is moved downward to make the gripping portion 452 grip the electronic component 1 by using the Z stage integrated in the gripping device 450, the gripping device 450 may be moved as is onto the image pickup apparatus 414, and the posture of the electronic component 1 is confirmed by using the image pickup apparatus 414. Subsequently, the posture of the electronic component 1 is adjusted by using a fine-adjustment mechanism integrated in the gripping device 450. Then, the gripping device 450 is moved onto the inspection bed 416, and then the Z stage integrated in the gripping device 450 is moved to set the electronic component 1 on the inspection bed 416. Since the posture of the electronic component 1 is adjusted by using the fine-adjustment mechanism of the gripping device 450, the electronic component 1 can be set to a right position on the inspection bed 416. When the inspection of the electric characteristics of the electronic component 1 is terminated, the electronic component 1 is taken out from the inspection bed 416, then the Y stage 432 and the X stage 436 are moved to move the gripping device 450 to a position above the downstream stage 412d, and then the electronic component 1 is placed on the downstream stage 412d. Subsequently, the downstream stage 412d is moved to convey the electronic component 1 after having inspected to a predetermined position.
As illustrated as a hatched portion in
Provided in the interior of the printing apparatus 600 are a printhead 620 configured to reciprocate in a primary scanning direction on the printing medium 2, and a guide rail 610 configured to guide the movement of the printhead 620 in the primary scanning direction. The illustrated printhead 620 includes a printing portion 622 configured to eject ink on the printing medium 2, and a scanning portion 624 configured to cause the printhead 620 to scan in the primary scanning direction. A plurality of ejection nozzles are provided on a bottom surface side of the printing portion 622 (a side facing the printing medium 2), and ink may be ejected from the ejection nozzles toward the printing medium 2. The scanning portion 624 is provided with piezoelectric motors 100m and 100s as drive units mounted thereon. The projecting portion (illustration is omitted) of the piezoelectric motor 100m is pressed against the guide rail 610. Therefore, by operating the piezoelectric motor 100m, the printhead 620 may be moved in the primary scanning direction. The projecting portion 122 of the piezoelectric motor 100s is pressed against the printing portion 622. Therefore, by operating the piezoelectric motor 100s, the bottom surface side of the printing portion 622 can be brought toward and away from the printing medium 2. The printing apparatus 600 also includes a cutting mechanism 630 configured to cut a roll paper 604 mounted thereon. The cutting mechanism 630 includes a cutter holder 632 having a paper cutter 636 mounted on a distal end thereof, and a guide shaft 634 configured to extend in the primary scanning direction so as to penetrate through the cutter holder 632. A piezoelectric motor 100c is mounted in the cutter holder 632, and a projecting portion, not illustrated, of the piezoelectric motor 100c is pressed against the guide shaft 634. Therefore, when the piezoelectric motor 100c is operated, the cutter holder 632 moves in the primary scanning direction along the guide shaft 634, and the paper cutter 636 cuts the roll paper 604. The piezoelectric motor 100 can be used as the drive unit for feeding the printing medium 2.
The rotary disc 702 is provided with a coaxial small gear 702g, and the gear 702g engages the gear train 704. Therefore, the rotation of the rotary disc 702 is transmitted to the gear train 704 while being reduced in speed at a predetermined ratio. The rotation of the gear is transmitted to the hand which indicates time of day to indicate time of day. If the projecting portion 122 of the piezoelectric motor 100 is provided in a state of being pressed against an outer peripheral surface of the rotary disc 702, the piezoelectric motor 100 can be used as a drive unit for driving the rotary disc 702.
The piezoelectric motor and various devices and apparatus having the piezoelectric motor mounted thereon have been described. However, the invention is not limited to the example, the modifications, and application examples, and may be implemented in various modes without departing the gist of the invention.
For example, in the example and the modifications, the mode in which the reinforcing member 140 is provided in tight contact with the supporting portions 128, the mode in which the supporting portions 128 are bent, the mode in which the thickness of the supporting portion 128 is set to be thicker than the shim plate 120, and the mode in which the supporting portions 128 are formed of a material (including the vibration damping material) having a higher rigidity than that of the shim plate 120 have been employed in order to set the rigidity of the supporting portions 128 to be higher than that of the shim plate 120. However, two or more of these modes may be combined. In this configuration, the rigidity of the supporting portions 128 may further be enhanced.
The entire disclosure of Japanese Patent Application No. 2013-252753, filed Dec. 6, 2013 is expressly incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-252753 | Dec 2013 | JP | national |
