JPS6317716A - Piezoelectric drive type conveying device - Google Patents

Abstract

PURPOSE:To increase the speed of conveyance while variations in the speed of conveyance are decreased, by forming a vibration excitor attached to one side surface of a resilient plate, for vibrating a conveying member, with two upper and lower piezoelectric elements which are distorted for vibration in opposite directions from each other. CONSTITUTION:Leaf spring type resilient plates 23 are attached in parallel with each other to both inclined surfaces 21a, 21b of an attaching seat 21 on the upper side of a base bed 20. Plate-like piezoelectric elements 24-27 are attached on both side surfaces of each resilient plate 23, two for each of upper and lower sides, in such an arrangement that upper piezoelec tric elements have poles which are reverse to that of the lower piezoelectric elements, so that a vibration excitor 22 is formed. The upper ends of the resilient members 23 are attached by screws onto inclined surfaces 29a on both sides of the attaching seat 29. A trough 28 serving as a conveying member is secured on the mounting seat 29, and an article 32 is set on the trough 28. The resilient members 23 and the piezoelectric elements 24-27 are applied with a.c. voltage through lead wires 30a, 31a. The trough 28 is vibrated up and down in an oblique direction to convey leftward the article 32 to be conveyed. With this arrange ment, the speed of conveyance is increased thereby it is possible to reduce variations in the speed of conveyance due to the difference in weight among articles to be conveyed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to conveying relatively small articles such as electronic parts or mechanical parts by means of vibration, and in particular uses a piezoelectric element as the vibration source. The present invention relates to the piezoelectric side moving transfer device used.

(Prior art) As an example of a conventional piezoelectric side moving transfer device,
There is a linear parts feeder shown in Japanese Patent No. 1087 or Japanese Utility Model Application No. 57-46517, but its configuration is
As shown in the figure. In this FIG. 10, 1 is a base, 2 is a lower frame fixed to the upper surface of the base 1, and an upper frame 4 is attached to both ends of this via two elastic plates 3.3 that stand up at an angle. supported horizontally. Reference numeral 5 denotes a trough serving as a conveying body fixed on the upper frame 4, on which the conveyed object 6 is placed. 7 is a plate-shaped piezoelectric element attached to the side surface of each elastic plate 3, and a terminal 8.7 is attached to the side surface of each elastic plate 3.
The AC voltage applied to 9 is applied via lead wires 8a and 9a. In this case, the elastic plate 3 and both piezoelectric elements 7, 7 constitute a bimorph 10 as a vibrating body, and when an alternating current voltage is applied to both piezoelectric elements 7, 7 so that their polarization directions are opposite, for example, The bimorph 10 is deflected in the direction of the arrow 11 by repeating the stretching motion in which one piezoelectric element 7 extends and the other piezoelectric element 7 contracts in the negative half cycle, and conversely, one contracts and the other extends in the negative half cycle. Vibrate. This deflection vibration causes the trough 5 to vibrate diagonally up and down in the direction shown by arrow 12, and by repeating the operation of jumping up the conveyed object 6 diagonally upward, it is moved along the trough 5 in the direction of arrow 13.

In this case, the conveyance speed of the conveyed object 6 is proportional to the vibration amplitude of the trough 5.

This type of piezoelectric drive type parts feeder has a smaller and simpler structure than electromagnetic drive feeders or electric vibration feeders, making it easier to handle and repair.In addition, it consumes less electricity, making it economical as well. Although it has many features such as having no concerns about noise problems, there is a problem in terms of conveyance speed, and the reason for this is described below.

That is, it is known that if an alternating current voltage with the same frequency as the natural frequency of the bimorph 10 is applied, the vibration amplitude will increase by ten times or more even with the same voltage due to a resonance phenomenon. However, even during resonance, if a large load is applied to the bimorph 10 in a direction that prevents its vibration, the vibration amplitude will drop rapidly.
It is necessary to minimize the load in the direction that hinders vibration.

As shown in FIG. 10, since the lengths of the two bimorphs 10 are the same and parallel to each other, the bimorphs 10
When the trough 5 vibrates in the direction of the arrow 11, the trough 5 always remains horizontal and vibrates diagonally downward (in the direction of the arrow 12). However, in the conventional device described above, since the angle of the connecting portion 4a of the upper frame 4 is always kept constant even during vibration, the angle θ (the first
(See Figure 1) vibrates to keep it constant, and this causes an excessive bending external force to be applied to the upper end of the elastic plate 3 in a direction that prevents the vibration. For this reason,
This has the drawback that the vibration amplitude of the bimorph 10 and, in turn, the vibration amplitude of the trough 5 becomes small, making it impossible to obtain a practical conveyance speed.

Therefore, in order to eliminate such drawbacks, a configuration as shown in FIG. 12 has been considered. That is, a connecting member 14 made of an elastic material is interposed between the upper end of the elastic plate 3 of the bimorph 10 and the trough 5, and this connecting member 14
The bending rigidity of the elastic plate 3 is set to a lower value than that of the elastic plate 3. As a result, during vibration, by elastically deforming the connecting member 14 with low bending rigidity as shown in FIG. 13, the angle change between the upper end of the elastic plate 3 and the trough 5 is allowed with a relatively small force. Correspondingly, the load in the direction that prevents vibration is reduced, and the vibration amplitude of the bimorph 10 is increased.

However, in this case, since the bending rigidity of the connecting member 14 is low, the displacement of the connecting member 14 changes greatly due to a change in the weight of the conveyed object, and this is the cause of a large change in the vibration amplitude of the trough 5 and thus the conveying speed. becomes. Incidentally, FIG. 5 shows the relationship between the burden of the transported object and the transport speed, and as shown by the - dotted chain line, the transport speed changes by about 20% due to a change in the weight of the transported object. When actually using a parts feeder on a production line,
It is an important condition to always supply conveyed objects to a predetermined station at constant time intervals, but the above-mentioned connection part 14
14, there is a problem in that the timing of feeding the conveyed object becomes unstable due to a change in the conveying speed due to a change in the weight of the conveyed object.

(Problems to be Solved by the Invention) As described above, if a connecting member with low bending rigidity is interposed between the elastic plate of the vibrating body and the conveying body, the vibration amplitude of the conveying body and the conveying speed will be reduced. can be increased to some extent, but on the other hand, there is a problem that the conveyance speed tends to change greatly depending on changes in the weight of the conveyed object, and the conveyance speed is not stable.

The present invention is intended to solve these drawbacks, and therefore, its purpose is to provide a piezoelectric side moving conveyance device that can sufficiently increase the conveyance speed and stabilize the conveyance speed regardless of changes in the weight of the conveyed object. is to provide.

[Structure of the Invention] (Means for Solving the Problems) The piezoelectric side moving conveyance device of the present invention includes a vibrating body for vibrating the conveyance body, and a plate-shaped piezoelectric element attached to the side surface of an elastic plate. The piezoelectric element is configured to bend and vibrate together with an elastic plate by applying a voltage to the piezoelectric element, in which the piezoelectric element is divided into upper and lower halves, and when a voltage is applied, the lower piezoelectric element and the upper piezoelectric element The piezoelectric element is configured to flex and vibrate in opposite directions.

(Function) Since the lower piezoelectric element and the upper piezoelectric element are flexed and vibrated in opposite directions, the vibration of the upper piezoelectric element causes the upper end portion of the elastic plate to move in the vibration direction of the entire vibrating body ( The piezoelectric element is warped in the opposite direction to the bending direction of the lower piezoelectric element. Therefore, the bending force applied to the elastic plate from the carrier side during vibration can be reduced, and the vibration amplitude of the vibrating body and, in turn, the vibration amplitude of the carrier can be increased. Moreover,
Since there is no need to interpose a connecting member with low bending rigidity between the elastic plate and the conveying body, there are problems caused by interposing the connecting member, namely, the conveyance speed changes greatly due to changes in the weight of the conveyed object. Problems can be resolved.

(Embodiment) Hereinafter, a first embodiment in which the present invention is applied to a linear parts feeder will be described with reference to FIGS. 1 to 5. First, the whole (
In Figure 2 showing the 1'4 configuration, 20 is the mounting seat 2 on the top surface.
1 is fixed, and 22 is a vibrating body, for example, a 113 structure in which two plate-shaped piezoelectric cords 24 to 27 are attached to both sides of an elastic plate 23 made of a leaf spring, with two plate-shaped piezoelectric cords 24 to 27 positioned above and below. be.

Therefore, this vibrating body 22 has a form in which a piezoelectric element is divided into upper and lower halves, unlike the conventional bimorph. For example, the lower end portions of each elastic plate 23 are screwed to the inclined surface portions 21a, 21a on both sides of the mounting seat 21 so that the two vibrating bodies 22 are parallel to each other with their fingers interposed diagonally in the vertical direction. Fixed. Reference numeral 28 denotes a trough serving as a conveyor, and sloped surface portions 29a, 2 on both sides of a mounting seat 29 fixed to the lower surface of the trough 28
The upper end of each elastic plate 23 is fixed to 9a by screws 1[-], thereby horizontally supporting the trough 28. In this case, as shown in FIG.
5 and the lower piezoelectric elements 26 and 27 have opposite polarities (the polarization polarities are indicated by + and - signs in FIG. 3). Then, the AC voltage applied to the terminal 30 is applied to the lead wire 30a.
The AC voltage applied to the back surface of each piezoelectric element 24 to 27 via the elastic plate 23 and applied to the terminal 31 is applied to the front surface of each piezoelectric element 24 to 27 via the lead wire 31a. There is.

Next, the operation of the above configuration will be explained. Both vibrating bodies 22
When an AC voltage is applied to each of the piezoelectric elements 24 to 27, the polarization of the upper piezoelectric elements 24 and 25 and the lower piezoelectric element 2
Since the polarization polarities of 6.27 and 6.27 are opposite to each other, as shown in FIG. 25 is deflected to the left, and then deflected in the opposite direction in a negative half cycle, repeating this motion to vibrate. With this vibration, the upper end portion of the elastic plate 23 vibrates so as to be displaced in the bending direction of the lower piezoelectric elements 26 and 27, causing the trough 28 to vibrate diagonally in the vertical direction. As a result, the conveyance object 32 on the trough 28 is repeatedly lifted diagonally upward, thereby moving the conveyance object 32 along the trough 28 to the left in the figure.

In this embodiment, since the lower piezoelectric elements 26, 27 and the upper piezoelectric elements 24, 25 are deflected and vibrated in opposite directions, the pressure on the upper side? Due to the vibration of the Ii elements 24 and 25, the upper end portion of the elastic plate 23 is warped in a direction opposite to the vibration direction of the vibration body 22 as a whole (the direction in which the lower piezoelectric elements 26 and 27 bend). Therefore, during vibration, the first end of the elastic plate 23 is bent along the inclined surface 29a of the mounting seat 29 by the lower piezoelectric elements 24 and 25, so that the elastic plate 23 is bent from the trough 28 side.
The bending force applied to the vibrating body 22, that is, the load in the direction that prevents the vibration of the vibrating body 22, can be reduced, the vibration amplitude of the vibrating body 22, and thus the vibration amplitude of the trough 28, can be increased, and a sufficient conveyance speed can be ensured. Moreover, since there is no need to interpose a connecting member with low bending rigidity between the elastic plate 23 and the tiger and flap 28, problems caused by interposing the connecting member, that is, the conveyance speed changes greatly due to changes in the weight of the conveyed object. This can solve the problem of Incidentally, according to the experimental results shown in FIG. 5, in this example, even if the weight of the transported object changes, the change in the transport speed is 596 or less, and the transport speed is stable. In addition, compared to those using low-rigidity connecting members, the elastic plate 2
3 and the trough 28, the mechanical strength is improved, and the life due to vibration fatigue can be more than doubled.

FIG. 6 shows a second embodiment in which the present invention is applied to a bowl-shaped parts feeder, which will be described below. Reference numeral 33 denotes a disc-shaped base, on the top surface of which a plurality of mounting seats 34 are provided at equal intervals on the same circumference. The lower end of the elastic plate 23 of the vibrating body 22 having the same configuration as that of the first embodiment is fixed to each mounting seat 34, so that each vibrating body 22
are arranged at equal intervals on the same circumference on the base 33, each inclined at a predetermined angle. Furthermore, each vibrator 22
A bowl 35 serving as a carrier is connected to the upper end of the elastic plate 23 .

In the bowl-shaped parts feeder having such a configuration, when an AC voltage is applied to the piezoelectric elements 24 to 27 of the vibrating body 22, the lower piezoelectric elements 26, 27 and the upper piezoelectric elements 24.
25 and vibrate in opposite directions.

Due to this vibration, the bowl 35 vibrates in a spiral direction (diagonally up and down in the circumferential direction), and the conveyed objects in the bowl 35 are sequentially conveyed along the spiral conveyance path 36 on the inner circumferential surface of the bowl 35, and the objects are conveyed at the exit of the bowl 35. It will be discharged from 36a.

In this case as well, since the lower piezoelectric elements 26, 27 and the upper piezoelectric elements 24, 25 are vibrated so as to be deflected in opposite directions, each elastic plate has an angle of 2°3.
The end portions are bent by the piezoelectric elements 24, 25 so as to maintain a substantially constant angle with respect to the lower surface of the bowl 35, and as in the first embodiment, the conveying speed can be increased and stabilized.

Note that the III structure of the vibrating body 22 is not limited to that of the above embodiment, and for example, as in the third embodiment shown in FIG.
A notch 37 may be formed at the inflection point at the center of 3, thereby increasing the amount of deformation of the elastic plate 23 and thus the vibration amplitude.

Furthermore, in the bowl-shaped parts feeder, since the bowl 35 is displaced by a certain amount in the circumferential direction, it is necessary to twist the elastic plate 23 by a certain amount. Therefore, from the bowl 35 to the elastic plate 2
In order to reduce the load in the twisting direction applied to the piezoelectric elements 24 to 27, as in the fourth embodiment shown in FIG.
It is also possible to give a gradient to the thickness of each. In this case, the smaller the thickness of the piezoelectric elements 24 to 27 (the distance between the electrodes), the larger the bending displacement.
There will be a twist added to it. For this reason, bowl 3
5 can also reduce the load in the twisting direction applied to the elastic plate 23, and the vibration amplitude of the bowl 35 can be further increased.

Historically, as in the fifth embodiment shown in FIG. 9, the attachment positions of the upper piezoelectric elements 24, 25 are shifted to the left side, and the attachment positions of the lower piezoelectric elements 26, 25 are shifted to the left side. A twist can be added to the elastic plate 23 even if the attachment position of '27 is shifted to the right side.

In the -11 embodiment, since the elastic plate 23 is used as a common electrode for the piezoelectric elements 24 to 27, the piezoelectric cords 24.
Although the polarization polarity of the piezoelectric elements 25 and the polarization polarity of the lower piezoelectric cords 26 and 27 are set to be opposite to each other, the present invention is not limited thereto. The polarity of the voltage may be reversed at the top and bottom.

[Effects of the Invention] As is clear from the above description, the present invention bends and vibrates the lower piezoelectric element and the upper piezoelectric element in opposite directions, so that the bending force applied to the elastic plate from the carrier side is reduced. can be made smaller, and the vibration amplitude and thus the conveyance speed can be increased. Moreover, since there is no need to interpose a connecting member with low bending rigidity between the elastic plate and the conveyor, the degree of change in conveyance speed due to changes in the weight of the conveyed object can be reduced, and the conveyance speed can be stabilized. It has excellent effects.

[Brief explanation of the drawing]

Figures 1 to 5 show a first embodiment in which the present invention is applied to a linear parts feeder. Figure 1 is a side view of the vibrating body during vibration, and Figure 2 is a side view of the entire body. , FIG. 3 is a side view of the vibrating body, FIG. 4 is a front view thereof, FIG. 5 is a diagram showing the relationship between the weight of the conveyed object and the conveyance speed, and FIG. FIG. 7 is a front view of the vibrating body showing the third embodiment of the present invention, and FIGS. 8(a) and (b) are the overall perspective view showing the second embodiment applied to a parts feeder. Front view and cross-sectional view of the vibrating body showing the fourth embodiment, FIGS. 9(a) and (b)
1 is a front view and a perspective view of a vibrating body showing a fifth embodiment of the present invention during vibration, and FIGS. 10 to 13 show conventional examples, and FIG. 10 is equivalent to FIG. 2. Figure 11 is a diagram for explaining the vibration form, Figure 12 is a perspective view of the whole,
FIG. 13 is a diagram for explaining the vibration form. In the drawing, 22 is a vibrating body, 23 is an elastic plate, 24 to 27 are piezoelectric elements, 28 is a trough (carrying body), and 35 is a bowl (carrying body). Figure 1 Figure 2 V Turtle Figure 3 Bird 4 Figure Weight of conveyed object (gx+σ゛) Figure 5 Figure 6 Figure 6 (a) (b) Figure 7 Figure 8 Figure 8 (a)
(b) Figure 9 Figure 11 Figure 12

Claims (1)

[Claims] 1. The vibrating body for vibrating the carrier is constructed by attaching a plate-shaped piezoelectric element to the side surface of an elastic plate, and by applying a voltage to the piezoelectric element, the piezoelectric element is caused to bend and vibrate together with the elastic plate. In the piezoelectric device, the piezoelectric element is divided into upper and lower halves, and the lower piezoelectric element and the upper piezoelectric element are bent and vibrated in opposite directions when a voltage is applied. Drive type conveyance device.