JP2022061711A - Work-piece conveyance device - Google Patents

Abstract

To provide a nonconventional work-piece conveyance device for realizing stable conveyance with small variation in amplitude, that suppresses jumping of a workpiece.SOLUTION: There are provided a vibrator 3A provided with a conveying surface 31 for performing conveying in a state where a work-piece is placed, and a vibration generating part 3B for generating vibrations of drawing an elliptic orbit to a conveying part 31 by generating a compressional wave including a compressive strain and a tensile strain in a direction along a work-piece conveyance direction, to the vibrator 3A, in at least two modes. A piezo-electric element 36 is arranged at a position of physically roughly symmetrical to an upper face side and a lower face side of the vibrator 3A to constitute the vibration generating part 3B.SELECTED DRAWING: Figure 2

Description

The present invention relates to a work transfer device that conveys a work by generating a traveling wave on the transfer surface.

In recent years, the miniaturization of electronic components such as chip capacitors has progressed, and the demand for high-speed processing has increased for the production equipment thereof. High-speed transfer of workpieces is also required for parts feeders, but if the amplitude is increased to increase the speed, problems such as dropping or clogging of workpieces will occur in the interface section with the next process equipment. Therefore, it has been studied to increase the frequency of the drive device, reduce the displacement amplitude, and increase the transport speed. However, since the sensitivity of the human ear approaches 1 kHz to 4 kHz, a noise problem occurs. Further, when the frequency is increased, elastic deformation is likely to occur in the transport path or the like, which hinders the normal transport of the work. Therefore, with the current structure that resonates with a leaf spring, there is a limit to improving the transport speed.

Therefore, as shown in Patent Document 1, there has been proposed a parts feeder that transports a work by generating a bending traveling wave in an ultrasonic region in a transport portion and elliptical vibration of a transport surface.

The work transport device described in Patent Document 1 includes a transport surface having a track shape on which a work is placed and a traveling wave generating means for generating a traveling wave circulating on the transport surface, and the traveling wave generating means is generated. It is configured to transport the work on the transport surface by the traveling wave.

In such a work transfer device, the traveling wave becomes a bending traveling wave due to the occurrence of bending on the conveying surface. When a bending traveling wave is generated, an elliptical motion in the side view of the transport direction reference is generated at each position of the transport surface, and the work placed on the transport surface is a traveling wave due to the horizontal velocity component in this elliptical motion. It is transported in the direction opposite to the traveling direction of.

Patent Document 1 also proposes a configuration in which a plurality of slits extending in the width direction are formed on the transport surface in the circumferential direction (FIGS. 11 and 12 of Patent Document 1). By forming the slit on the transport surface in this way, the horizontal velocity component of the elliptical motion generated on the transport surface due to the bending traveling wave can be increased.

Japanese Unexamined Patent Publication No. 2017-034331

However, in the conventional work transfer device using the bending traveling wave, the work jumps due to the vertical vibration of the elliptical motion on the transfer surface. Therefore, in order to suppress the jumping of the work, it is desirable to increase the horizontal amplitude with respect to the vertical amplitude in the elliptical motion. When the slit structure is used, it has the effect of increasing the amplitude in the horizontal direction, but it is still insufficient, and new problems such as the posture of the work being disturbed at the slit portion occur.

It is conceivable to use longitudinal waves to generate vibrations with large amplitude in the horizontal direction. If a sparse and dense wave including compression strain and tensile strain in the direction along the work transport direction is generated in a vibrating body having a transport surface in at least two modes, one point on the transport surface is in the work transport direction in a lateral view. Can generate vibrations that draw an elliptical orbit with a long axis. The work transport direction is, that is, the traveling direction of the traveling wave, and in the case of the bowl feeder and the linear feeder, it is the circumferential direction of the annulus and the oval.

In a parts feeder that uses such longitudinal wave traveling waves, the horizontal component of the elliptical vibration of the transport surface can be increased, so the workpiece is transported at high speed while suppressing the vertical vibration amplitude that causes the workpiece to jump. You can expect to do it.

In this case, the vibration source (piezoelectric element) for generating the longitudinal wave traveling wave is attached to the bottom surface (the surface opposite to the transport surface) or the side surface of the vibrating body in the same manner as the device using the deflection traveling wave. The structure is conceivable.

However, when an attempt is made to generate a compressional wave due to compression and tension in the vibrating body by utilizing the expansion / contraction operation of the piezoelectric element from such a position, a force that causes bending of the vibrating body as described later based on FIG. Since (bending moment) is added, it may excite unnecessary vibrations that accompany bending, in addition to the longitudinal wave that you want to generate. Further, especially in the structure in which the vibrating element is attached to the bottom surface of the vibrating body, the structure becomes asymmetrical in the vertical direction. It may become.

As a result, the work transfer speed varies and the work jumps. Such a problem is a problem peculiar to a longitudinal wave, which does not occur in a device using a deflection traveling wave which is a transverse wave.

INDUSTRIAL APPLICABILITY The present invention provides a work transfer device that does not exist in the past, in which a work transfer device that transfers a work by generating a traveling wave on the transfer surface suppresses the jump of the work and realizes stable transfer with a small amplitude variation. The purpose is to provide.

The present invention has taken the following measures in order to achieve the above object.

That is, the work transport device of the present invention has a vibrating body having a transporting portion for transporting the work in a mounted state, and a compression strain and a tensile strain in the vibrating body in a direction along the transport direction of the work. The transport portion is provided with a vibration generating portion that generates vibration that draws an elliptical orbit by generating the vibration in at least two modes, and the vibration generating portion is provided with respect to the upper surface side and the lower surface side of the vibrating body. It is characterized in that it is arranged and configured at positions that are physically substantially symmetrical.

Here, "physically symmetric" means that the vibration source is arranged so that the vibration force acts on the neutral axis, and the point of action of the elastic force and the inertial force when longitudinal vibration occurs is on the neutral axis. A configuration that roughly matches. The "neutral axis" refers to an axis in which tension and compression are balanced against bending and stress is not generated when the vibrating body is viewed from the thickness direction. A surface in which such axes are connected is also called a neutral surface.

By doing so, since a moment that causes bending of the vibrating body is not generated, it is possible to suppress the generation of unnecessary vibration. As a result, the variation in amplitude is small, the traveling wave ratio is improved, and it is possible to realize stable transport with little variation in speed. Further, in the configuration in which the vibration generating portion is arranged on the bottom surface, the asymmetry becomes larger depending on the shape such as the thickness of the vibration source, so that it is difficult to freely design the shape of the vibration source. According to the present invention, vertical symmetry can be obtained, so that the degree of freedom in design is increased. Therefore, for example, it is easy to design such that the vibration source is thickened to increase the capacitance.

In this case, it is preferable that the vibration source is arranged along the neutral axis of the vibrating body within the wall thickness of the vibrating body. When the upper side and the lower side are the same single material, the neutral axis is near the center in the thickness direction, and physical symmetry can be obtained by arranging the vibration source here. Further, even if there is some asymmetry, physical symmetry can be obtained if the position of the neutral axis is shifted in the thickness direction. Since it is arranged within the thickness, both sides of the vibration source are sandwiched between the vibrating bodies, and it is difficult for a failure such as cracking to occur.

Further, it is preferable that the vibrating body is composed of an upper vibrating body and a lower vibrating body, and the upper vibrating body and the lower vibrating body are arranged so as to sandwich the vibration source. With such a configuration, it is easy to make using the half-split structure, and the electrodes can be easily pulled out.

Further, it is preferable that all or the main parts of the material or shape of the upper vibrating body and the lower vibrating body are the same, and the vibration source is arranged on a substantially neutral axis. In such a case, if the upper side and the lower side are the same single material, the neutral axis is near the center in the thickness direction, and if the vibration source is placed here, physical symmetry can be obtained. Will be easy to realize.

Further, it is preferable that the physical asymmetry between the upper vibrating body and the lower vibrating body is complemented by imparting a shape different from the other to one of the upper vibrating body or the lower vibrating body. Even if there is a difference in the shape of the upper vibrating body and the lower vibrating body, or even if there is a difference in the material and thickness, it is relatively easy and appropriate to secure physical symmetry by complementing with the shape. can.

Further, it is preferable that the vibration source is arranged in a pair at a position displaced toward the upper surface side and a position displaced toward the lower surface side inside the vibrating body. By doing so, since the combined exciting force acts on the neutral axis, it is possible to increase the exciting force while ensuring physical symmetry.

According to the present invention described above, since the traveling wave due to uniform elliptical vibration having the long axis in the transport direction can be generated on the transport surface by the sparse and dense wave, the jump of the work is suppressed and the amplitude variation is small. It becomes possible to realize stable transportation.

The perspective view which shows the schematic structure of the work transfer apparatus which concerns on this embodiment. The figure which shows the transport part of FIG. The schematic diagram which shows the structure for vibrating a vibrating body in a work transfer apparatus. The figure which shows the arrangement structure of the piezoelectric element which is a vibration source. The figure which shows the comparative example of FIG. The figure explaining the generation of a longitudinal wave by a compressional wave. The figure which shows how the traveling wave by a longitudinal wave propagates. The figure which showed the deformation state which appears in the vibrating body under the vibration source arrangement of FIGS. 4 and 5. The figure explaining the neutral axis and the physical symmetry in the case of a bowl feeder. The figure explaining the structure which complements the physical symmetry by the shape. The figure corresponding to FIG. 4 which shows the modification of this invention. The figure corresponding to FIG. 4 which shows the other modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The work transfer device (parts feeder) 1 according to the present embodiment shown in FIG. 1 has a disk-shaped bowl feeder 3 and a linear feeder 4 connected so as to extend in the tangential direction of the bowl feeder 3 on the base portion 2. To prepare for.

The bowl feeder 3 includes a bowl feeder side transport portion 31 which is a disk-shaped member. The bowl feeder side transport portion 31 is fixed to the base portion 2 by a fixing portion 32 located at the center. As shown in the figure, the upper surface of the bowl feeder side transport portion 31 has a recess 33 in which the work is loaded, and has a mortar-shaped slope 34 around the recess 33, from the peripheral edge of the recess 33. A spiral truck 35 is formed as a transport truck for transporting the work over the upper edge of the slope 34. The spiral truck 35 has a groove that rises while drawing a spiral, and the groove bottom is a transport surface 351. The work is transported by deforming the transport surface 351 so as to undulate by the traveling wave generating portion 3B (see FIG. 3).

The linear feeder 4 includes a linear feeder side transport unit 41 which has an oval shape in a plan view. The linear feeder side transport portion 41 is fixed to the base portion 2 by a fixing portion 42 located at the center in the width direction. The transport truck in the linear feeder 4 is composed of a main truck 43 and a return truck 44. The main track 43 has a linear groove extending in the longitudinal direction on the upper surface of the linear feeder side transport portion 41, and the groove bottom is the transport surface 431. The return track 44 has an oval groove located inside the width direction of the main track 43 on the upper surface of the linear feeder side transport unit 41, and the groove bottom is the transport surface 441. The work is conveyed by deforming these transport surfaces 431 and 441 so as to undulate by the traveling wave generating portion 4B (similar configuration to the traveling wave shipping portion 3B for the bowl feeder 3 in FIG. 3).

In each of the feeders 3 and 4, a plurality of workpieces may be transported in a state of being aligned adjacent to each other on the transport surfaces 351 and 431, 441, or may be transported at intervals.

Among the works on the main track 43, the work having an inappropriate posture or the like is moved from the main track 43 to the return track 44 by a moving means (air nozzle or the like) (not shown). In the schematic diagram of the figure, the return track 44 is drawn to circulate, but in reality, the work transferred to the return track 44 is returned to the bowl leader 3 or rejoined to the main track 43 as appropriate. The configuration of is adopted.

Since the mechanism for transporting the work is common between the bowl feeder 3 and the linear feeder 4, the configuration of the present embodiment will be described below by taking either the bowl feeder 3 or the linear feeder 4 as an example.

First, the basic configuration will be described by taking the bowl feeder 3 as an example. As shown in FIGS. 1 to 3, the bowl feeder 3 includes a vibrating body 3A and a vibration generating unit 3B. The vibrating body 3A is a part of the bowl feeder side transport portion 31, and is represented as an annular one. The vibrating body 3A is an elastic body and is made of a material that serves as a medium for transmitting waves. The vibrating body 3A of the present embodiment is not made of solid metal having a vibration source attached to the lower surface or the side surface, but has a structure in which a piezoelectric element 36 which is a vibration source is embedded inside. This will be described later.

As shown in FIG. 3, the vibration generating section 3B applies an alternating voltage from the vibrating section 37 to the piezoelectric element 36, which is a vibrating source, in order to generate a sparse and dense wave in the vibrating body 3A, and is circumferential to the piezoelectric element 36. The extension operation and the contraction operation in the (work transport direction, traveling direction of the traveling wave) are performed. Due to the Poisson effect in the vibrating body 3A, this sparse and dense wave causes tensile strain as shown by the arrow (practice) A1 in the figure and arrow (broken line) A2 in the direction (circumferential direction) along the transport direction of the work as shown in FIG. Along with such compression strain, displacement B1 that contracts in the thickness direction orthogonal to the transport direction and displacement B2 that expands are caused.

As shown in FIG. 6, the vibrating body 3A has a plurality of standing wave modes (natural modes) of longitudinal waves, which are sparse and dense waves, in which tensile strain and compression strain are alternately generated along the circumferential direction. In the present embodiment, a standing wave in 0 ° mode and a standing wave in 90 ° mode, which are two standing waves having almost the same natural frequency and a spatial phase shift of 90 °, are combined. The peaks and valleys shown in FIG. 7 are, for example, traveling waves traveling clockwise as shown by the arrows. The "standing wave" is a wave (longitudinal wave) generated at a fixed position in the circumferential direction of the vibrating body 3A.

Since the mechanism of the movement of the medium itself in the standing wave of the longitudinal wave is known, detailed description thereof will be omitted.

As for the medium, in each of FIGS. 6 (a) and 6 (b), the upper figure shows the state in which the vibrating body 3A is deformed by the sparse and dense wave, and the lower figure shows the sparse and dense state by using vertical lines indicating sparse and dense. It is written together. As can be seen from these figures, in FIGS. 6A and 6B, the sparse part and the dense part are periodically replaced with time along the circumferential direction. In FIG. 6A, the position A and the position B are the positions of the “antinode” in the displacement distribution of the longitudinal wave, and the positions C and D are the positions of the “nodes”. At position C, the medium is "sparse" due to the occurrence of tensile strain, and at position D, the medium is "dense" due to the occurrence of compressive strain. Comparing FIGS. 6 (a) and 6 (b), the distorted states of the positions of the bellies A and B do not change, and the density of the nodes C and D is reversed.

As the vibrating body 3A expands and contracts in the circumferential direction, it expands and contracts in the thickness direction by the amount of change according to the Poisson's ratio. From the definition of Poisson's ratio, the strain in the thickness direction is inversely related to the strain in the circumferential direction. That is, the vibrating body 3A contracts in the thickness direction at the pulling position C and expands in the thickness direction at the compression position D. By generating displacements having different 90 ° phases at the positions of the 0 ° mode and the 90 ° mode, a flat elliptical vibration R having the traveling direction as the long axis is formed as shown in FIG. 6 (b).

The work W comes into contact with the transport surface at the upper portion of the elliptical vibration R, and a transport force M is generated. In the longitudinal wave, the long axis of the ellipse faces the transport direction as compared with the transverse wave, and the vertical displacement is small, so that the jump of the work W is small and an effective transport force M is exhibited.

As shown in FIG. 3, the vibration generating unit 3B has a plurality of vibration source piezoelectric elements 36 that apply the compression strain and the tension strain to the vibrating body 3A. In the present embodiment, the piezoelectric element 36 is not attached to the lower surface (or side surface) of the vibrating body 3A as shown in FIG. 5, but the piezoelectric element 36 is placed within the thickness of the vibrating body 3A as shown in FIG. The vibrating body A is configured by arranging the vibrating body A. As shown in FIG. 3, each piezoelectric element 36 is arranged so that the polarization directions (“+” and “−” in the figure) are switched at a pitch of 1/2 (λ / 2) of the wavelength of the stationary wave mode. The first group (first piezoelectric element group) 36A and the first group 36A are arranged at positions deviated from each other in the frequency division direction by 1/4 wavelength (λ / 4), and the standing wave is the same as the first group 36A. It is composed of a second group (second piezoelectric element group) 36B arranged so that the polarization directions are switched at a pitch of 1/2 of the wavelength of the mode. That is, the plurality of displacement generation units 36 are divided into groups 36A and 36B having numbers corresponding to the number of modes (two in this embodiment).

As shown in FIG. 3, the vibrating unit 37 includes a control unit 371 that applies a sine wave having a frequency corresponding to a unique mode in which a longitudinal wave is generated to the piezoelectric element 36, and the control unit 371 is attached to the piezoelectric element 36. It is connected. The control unit 371 inputs sine waves having different phases to the piezoelectric element 36 at each of the plurality of groups 36A and 36B, respectively. Specifically, the sine wave related to the AC voltage is divided into two systems, and the phase shifter 371d shifts the phase of one system in time. Although not shown, the control unit 371 can adjust the frequency of the sine wave to increase or decrease. The original sine wave and the phase-shifted sine wave 371a are amplified by the amplifiers 371b and 371c, respectively, and then applied to the piezoelectric elements 36 belonging to each group 36A and 36B via the energized ends 37a and 37b. In the present embodiment, for the piezoelectric element 36 belonging to each group 36A and 36B, the frequency is almost the same as the natural frequency in the 0 ° mode and the 90 ° mode, and the standing wave in the 0 ° mode and the 90 ° mode is the time. A sine wave having a temporal phase difference is applied in the phase shifter 371d so that the phase shifts by 90 °.

Each piezoelectric element 36 is arranged at an antinode position in the displacement distribution of the longitudinal wave standing wave mode. Of the two standing wave modes that are spatially out of phase by 90 ° due to the sine wave applied from the control unit 371 to the piezoelectric element 36, one standing wave mode is vibrated by the one piezoelectric element group 36A. The other standing wave mode is vibrated by the other piezoelectric element group 36B with the phase shifted by 90 ° in time.

As a result, as shown in FIGS. 6 and 7, a standing wave of a longitudinal wave is generated in the vibrating body 3A instead of a transverse wave (in the case of a bending progressive wave). Then, by generating a standing wave in a plurality of (two in this embodiment) standing wave modes that are spatially and temporally out of phase, the traveling wave can be made to travel in the circumferential direction.

In the present embodiment, as shown in FIG. 4, the piezoelectric element 36, which is a vibration source, is arranged within the wall thickness of the vibrating body 3A because the position of the piezoelectric element 36 is located on the upper surface side and the lower surface side of the vibrating body 3A. On the other hand, this is to make it physically substantially symmetrical. That is, the purpose of such an arrangement configuration is to make the points of action of the elastic force and the inertial force when the longitudinal vibration occurs approximately coincide with the neutral axis N. As described above, the neutral axis N refers to an axis in which tension and compression are balanced against bending and stress is not generated when the vibrating body 3A is viewed from the thickness direction (longitudinal cross-sectional direction). Specifically, the present embodiment has a configuration in which the upper vibrating body 3A1 and the lower vibrating body 3A2 are arranged so as to sandwich the piezoelectric element 36 which is the vibration source, preferably a sandwich structure with a half split, and the upper vibrating body 3A1. The material of the lower vibrating body 3A2 is the same, the shape such as the thickness is substantially the same, and the piezoelectric element 36 which is the vibration source is arranged along the neutral axis N of the vibrating body 3A.

In contrast to FIG. 4, the configuration of FIG. 5 is the same because the expansion and contraction of the piezoelectric element 36 occurs on the lower surface (or side surface) of the vibrating body 3A, and compression and pulling are performed from this position in the transport direction with respect to the entire vibrating body 3A. As shown by an arrow in the figure, the farther the position is from the piezoelectric element 36, the larger the displacement of the vibrating body 3A due to the bending moment in the bending direction.

FIG. 8A is a diagram showing a deformation state appearing in the vibrating body 3A under the piezoelectric element arrangement shown in FIG. 4, and FIG. 8B is a diagram showing the deformation state appearing in the vibrating body 3A under the piezoelectric element arrangement shown in FIG. It is a figure showing the deformation state appearing in the vibrating body 3A.

In FIG. 8A, the horizontal compression and tension states are represented by the intervals of vertical lines indicating sparseness and density. The place indicated by the reference numeral P is a place where the displacement in the horizontal direction is small, and the place indicated by the reference numeral Q is a place where the displacement in the horizontal direction is large. On the contrary, the displacement in the thickness direction is large in the place P where the displacement in the horizontal direction is small, and the displacement in the thickness direction is small in the place Q where the displacement in the horizontal direction is large. Looking at the intervals between the vertical lines that represent sparseness at these P and Q positions, the shape of the vertical lines, and the extending direction, the sparseness is drawn by vertical lines that extend above and below the neutral axis N near P and Q. Is approximately orthogonal to the neutral axis N and extends symmetrically. Looking at the upper transport surface 351, the peak position and the valley position are smoothly continuous at a predetermined cycle, and an ideal longitudinal wave traveling wave is formed on the transport surface 351 by uniform elliptical vibration. You can see that there is.

On the other hand, in FIG. It extends from the direction orthogonal to N in an asymmetrically curved direction and is irregularly distorted. Looking at the upper transport surface 351', the peak position and the valley position are distorted and discontinuous. A smooth traveling wave is not formed on the transport surface 351'.

From this, it can be seen that in FIG. 8A, the jumping of the work is suppressed as compared with FIG. 8B, and stable transfer with a small amplitude variation can be realized.

In the bowl feeder 3, the vibrating body is described as an annular shape in FIG. 2, but if necessary, a neutral shaft N exists in a mortar shape at substantially the center of the upper surface and the lower surface as shown in FIG. 9A. In this case, the piezoelectric element is arranged along the neutral axis N, or as shown in FIG. 9B, a dummy recess 34'which is physically equivalent to the recess 34 of the bowl feeder 3 is provided on the lower surface side. In the case of forming, physical symmetry can be ensured by appropriately adopting an embodiment in which the piezoelectric element is arranged along the planar neutral axis N.

As for the track, for example, as shown in FIG. 10, a dummy track 35'that can secure physical symmetry with the track 35 of the upper vibrating body 3A1 is provided on the lower surface side of the lower vibrating body 3A2 as needed. Is also secured. That is, including the case of FIG. 9B, the physical asymmetry between the upper vibrating body 3A2 and the lower vibrating body 3A2 is, if necessary, one of the upper vibrating body 3A1 or the lower vibrating body 3A2 and the other. Can be complemented by imparting different shapes. Therefore, even if there is a difference in the shape of the upper vibrating body 3A1 and the lower vibrating body 3A2, or even if there is a difference in the material and the thickness, physical symmetry is ensured by using the shape complement. be able to. In this sense as well, as shown in FIG. 10, the shape of the dummy truck 35'is not necessarily the same as that of the truck 35 of the transport portion.

The measures shown in FIGS. 9 (a), 9 (b) and 10 above can be similarly adopted in the linear feeder 4.

As described above, the work transfer device of the present embodiment is along the transfer direction of the work to the vibrating bodies 3A and 4A having the transporting portions 31 and 41 for transporting the work in a mounted state and the vibrating bodies 3A and 4A. The transport units 31 and 41 are provided with vibration generating units 3B and 4B that generate vibrations that draw an elliptical trajectory by generating a compressional strain and a tensile strain in the direction in at least two modes, and generate vibration. Piezoelectric elements 36 and 46, which are vibration sources of the vibration generating parts 3B and 4B, are arranged at positions where the parts 3B and 4B are physically substantially symmetrical with respect to the upper surface side and the lower surface side of the vibrating bodies 3A and 4A. It is characterized by being configured in.

By doing so, since a moment that causes bending is not generated in the vibrating bodies 3A and 4A, it is possible to suppress the generation of unnecessary vibration. As a result, the variation in amplitude is small, the traveling wave ratio is improved, and it is possible to realize stable transport with little variation in speed.

Further, in the configuration in which the piezoelectric element 36 which is the vibration source is arranged on the bottom surface, the asymmetry becomes larger depending on the shape such as the thickness of the piezoelectric element 36, so that the shape of the piezoelectric element 36 can be freely designed. Although it was difficult, according to this embodiment, vertical symmetry can be obtained, so that the degree of freedom in design is increased. Therefore, for example, it becomes easy to design such that the piezoelectric element 36 is thickened to increase the capacitance.

Further, the piezoelectric element 36, which is a vibration source, is arranged along the neutral axis N of the vibrating bodies 3A and 4A within the wall thickness of the vibrating bodies 3A and 4A. Therefore, since the piezoelectric element 36 is arranged within the thickness, both sides of the piezoelectric element 36 are sandwiched by the vibrating body, and it is difficult for a failure such as cracking to occur.

Further, the vibrating bodies 3A and 4A are composed of the upper vibrating body 3A1 (4A1) and the lower vibrating body 3A2 (4A2), and the upper vibrating body 3A1 (4A1) sandwiches the piezoelectric elements 36 and 46 which are vibration sources. ) And the lower vibrating body 3A2 (4A2) are arranged. Therefore, it is easy to make by using the half-split structure, and the electrode can be easily pulled out.

Further, all the materials or shapes of the upper vibrating body 3A1 (4A1) and the lower vibrating body 3A2 (4A2) are the same, and the vibration source is arranged on the substantially neutral axis N. Therefore, physical symmetry can be obtained with a simple structure.

Further, the physical asymmetry between the upper vibrating body 3A1 (4A1) and the lower vibrating body 3A2 (4A2) is different from the other in one of the upper vibrating body 3A1 (4A1) or the lower vibrating body 3A2 (4A2). It can also be complemented by giving a shape. As a result, even if there is a difference in the shape of the upper vibrating body 3A1 (4A1) and the lower vibrating body 3A2 (4A2), or even if there is a difference in the material and thickness, it is relatively easy to supplement with the shape. Appropriate physical symmetry can be ensured.

Through the above, the work transfer device of the present embodiment can generate a traveling wave on the transport surface based on elliptical vibration having a long axis in the transport direction by a sparse and dense wave, suppresses the jump of the work, and has a variation in amplitude. It is possible to realize stable transportation with a small amplitude.

Although one embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment.

For example, when the upper and lower sides of the vibrating body are made of a single material, the neutral axis is near the center in the thickness direction, and if a vibration source is placed here, physical symmetry can be obtained, but there is some asymmetry. However, by shifting the position of the neutral axis in the thickness direction, it can be adjusted so that physical symmetry can be obtained.

Further, as shown in FIG. 11, a surface layer 30 made of a material having a sufficiently low density and Young's modulus such as a resin or a thin material such as a coating on the surface of either the upper vibrating body 3A1 or the lower vibrating body 3A2. However, if it hardly contributes to the position of the neutral axis N, the elastic force, and the inertial force, the physical symmetry can be maintained. Of course, as described above, the neutral axis N may be shifted as necessary, or the lower vibrating body 3A2 (4A2) or the like may be complemented by the shape to enhance the physical symmetry.

Further, as shown in FIG. 11, the piezoelectric element 36, which is a vibration source, is arranged in a pair in a vertically symmetrical positional relationship between the position displaced toward the upper surface side and the position displaced toward the lower surface side inside the vibrating body 3A. You may. By doing so, since the combined exciting force acts on the neutral axis N, it is possible to increase the exciting force while ensuring physical symmetry.

In addition, various modifications can be made without departing from the spirit of the present invention, such as making the piezoelectric element a multi-layer structure or configuring the vibration source other than the piezoelectric element.

In addition, even if the thickness of the upper elastic body and the lower elastic body are slightly different due to the characteristics such as rigidity, the physical symmetry of the upper elastic body and the lower elastic body can be changed by different materials. Can absorb the balance.

3A, 4A ... Vibrating body 31, 41 ... Conveying part 3B, 4B ... Vibration generating part 3A1, 4A1 ... Upper vibrating body 3A2, 4A2 ... Lower vibrating body 36, 46 ... Excitation source (piezoelectric element)
N ... Neutral axis

Claims (3)

A vibrating body having a transport surface for transporting the workpiece in a mounted state,
A vibration generating unit that generates a vibration that draws an elliptical orbit in the transporting unit by generating a compressional strain and a tensile strain in the vibrating body in at least two modes. And, with
A work transfer device characterized in that the vibration generating portion is arranged at positions that are physically substantially symmetrical with respect to the upper surface side and the lower surface side of the vibrating body. The work transfer device according to claim 1, wherein the vibration source is arranged along the neutral axis of the vibrating body within the wall thickness of the vibrating body. The work transfer device according to claim 1 or 2, wherein the vibrating body is composed of an upper vibrating body and a lower vibrating body, and the upper vibrating body and the lower vibrating body are arranged so as to sandwich the vibration source. ..

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