CN108249109B

CN108249109B - Workpiece conveying device and adjusting method of workpiece conveying device

Info

Publication number: CN108249109B
Application number: CN201710665493.4A
Authority: CN
Inventors: 前田峰尚; 木村哲行; 大西孝信
Original assignee: Sinfonia Technology Co Ltd
Current assignee: Sinfonia Technology Co Ltd
Priority date: 2016-12-28
Filing date: 2017-08-07
Publication date: 2021-10-26
Anticipated expiration: 2037-08-07
Also published as: KR102433050B1; TWI750249B; TW201823122A; CN108249109A; KR20180076999A

Abstract

The invention provides a workpiece conveying device and an adjusting method thereof, wherein the required design precision and adjusting precision are relaxed to the extent that the conveying of workpieces is not hindered. The work conveying apparatus includes: the traveling wave generating device comprises a conveying part (31, 41) having a conveying surface (331, 431, 441) for conveying a workpiece in a state in which the workpiece is placed, and traveling wave generating means for generating a traveling wave on at least the conveying surface (331, 431, 441), wherein the traveling wave ratio is 0.13 or more, and the traveling wave ratio is defined as the ratio of the minimum amplitude of a position where the conveying surface (331, 431, 441) vibrates least within a predetermined range to the maximum amplitude of a position where the conveying surface (331, 431, 441) vibrates most within the predetermined range, among the vertical amplitudes of the conveying surface (331, 431, 441) caused by the traveling wave.

Description

Workpiece conveying device and adjusting method of workpiece conveying device

Technical Field

The present invention relates to a workpiece conveying apparatus for conveying a workpiece by generating a traveling wave on a conveying surface, and an adjustment method for the workpiece conveying apparatus.

Background

A conventional work conveying apparatus is described in patent document 1, for example. In such a workpiece conveying device, as in the principle described in patent document 1, a conveying surface that is in contact with the workpiece is deflected by a piezoelectric body to generate a traveling wave. Due to the traveling wave, an elliptical motion is generated at each position of the conveying surface, and the workpiece placed on the conveying surface is conveyed in a direction opposite to the traveling direction of the traveling wave in accordance with the elliptical motion.

In this work conveying apparatus, for example, two groups of piezoelectric bodies belonging to a plurality of groups arranged at substantially symmetrical positions in a cyclic shape are driven with different phases for each group, and standing waves (waves vibrating only at the same position) generated on a conveying surface by the piezoelectric bodies belonging to each group are synthesized to generate a traveling wave. However, the conveying surface cannot be made into a perfectly (ideal) symmetrical shape, and since the positions of the piezoelectric bodies with respect to the conveying surface and the driving states of the respective piezoelectric bodies vary, a perfect traveling wave cannot be generated, and since a traveling wave having a difference (a fraction of the magnitude) in amplitude at different positions in the circulating direction is actually generated, the conveying speeds of the workpieces differ at different positions of the conveying surface. Here, when the difference in amplitude is large at different positions in the circulation direction, the workpiece may be difficult to move or stop locally, thus hindering smooth conveyance of the conveying surface to the workpiece. However, it is very difficult to design and adjust the work conveying apparatus with high accuracy aiming at generating a perfect traveling wave having uniform amplitudes at different positions in the circulation direction, as described above.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-127655

Disclosure of Invention

Problems to be solved by the invention

Accordingly, an object of the present invention is to provide a workpiece conveying device capable of suppressing variation in conveying speed of workpieces. Further, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a work conveying apparatus and an adjustment method of the work conveying apparatus, in which required design accuracy and adjustment accuracy are relaxed to such an extent that work conveyance is not hindered.

Means for solving the problems

The work conveying apparatus of the present invention includes: a conveying unit having a conveying surface on which the workpiece is conveyed in a state in which the workpiece is placed; and a traveling wave generation means for generating at least a traveling wave on the transport surface, wherein the traveling wave generation means further includes a traveling wave ratio adjustment means for adjusting a traveling wave ratio that is a ratio of a minimum amplitude to a maximum amplitude of the traveling wave generated by the traveling wave generation means.

In the present invention, when the minimum amplitude and the maximum amplitude of the traveling wave generated by the traveling wave generating means are approximately equal to each other, the amplitude difference between the minimum amplitude and the maximum amplitude is approximately 0. This makes it easy to apply vibrations having the same amplitude at any position of the conveying surface, and thus, it is possible to suppress variations in the conveying speed of the workpiece. Therefore, the traveling wave ratio is adjusted by the traveling wave ratio adjusting means for adjusting the traveling wave ratio, which is the ratio of the minimum amplitude to the maximum amplitude of the traveling wave generated by the traveling wave generating means, and thus, the inconsistency in the workpiece conveying speed can be suppressed.

Further, the traveling wave ratio adjusting means may adjust the traveling wave ratio to 0.13 or more.

With this configuration, even if the generation of a perfect traveling wave is not aimed at, it is possible to form a workpiece conveying apparatus capable of conveying a workpiece without any trouble in actual use.

Further, the output of the traveling wave ratio may be adjusted by electrically operating the traveling wave generating means.

With this configuration, the traveling wave generating means can be electrically operated, and thus adjustment is easy.

The traveling wave generation means may be arranged at different positions in the workpiece conveying direction of the conveying section in at least two groups having different output phases, and the electrical operation of the traveling wave generation means may be an operation of changing at least one of a phase difference between the traveling wave generation means to which one of the at least two groups belongs and the traveling wave generation means to which the other group belongs, an amplitude ratio between the traveling wave generation means to which the one group belongs and the traveling wave generation means to which the other group belongs, and an excitation frequency of all the traveling wave generation means.

With this configuration, since the traveling wave ratio can be adjusted by changing any one of the phase difference, the amplitude ratio, and the excitation frequency, it is possible to select a change target suitable for adjustment according to the situation, and the degree of freedom of adjustment is improved.

In the workpiece conveying apparatus according to the present invention, the traveling wave ratio adjusting means may include at least one of means for adjusting the rigidity of the specific portion of the conveying section, means for adjusting the mass of the specific portion of the conveying section, and means for adjusting the damping characteristic of the vibration of the specific portion of the conveying surface.

As described above, the traveling wave ratio can be adjusted by adjusting at least one of the rigidity of the specific portion of the conveying unit, the mass of the specific portion of the conveying unit, and the damping characteristics of the vibration of the specific portion of the conveying surface.

In the workpiece conveying apparatus according to the present invention, the means for adjusting the rigidity of the specific portion of the conveying section may be attached to a portion of the conveying section other than the workpiece passage portion, and may be formed of a member configured to be elastically deformable together with the conveying section.

As described above, when the means for adjusting the rigidity of the specific portion of the conveying section is attached to a portion of the conveying section other than the workpiece passage portion and is formed of a member configured to be elastically deformable together with the conveying section, the means for adjusting the rigidity of the specific portion of the conveying section is elastically deformed together with the conveying section, and thus the traveling wave is not easily hindered.

Further, the present invention is a method of adjusting a work conveying apparatus including: a conveying unit having a conveying surface on which the workpiece is conveyed in a state in which the workpiece is placed; and a traveling wave generation unit that generates a traveling wave at least on the transport surface, the method including: an amplitude measuring step of measuring vertical amplitudes of the conveying surface at a plurality of positions in a workpiece conveying direction of the conveying surface; and a traveling wave ratio adjusting step of adjusting a traveling wave ratio, which is defined as a ratio of a minimum amplitude at a position where the vibration of the conveying surface is minimum within a predetermined range and a maximum amplitude at a position where the vibration is maximum within the predetermined range, obtained in the amplitude measuring step, to a predetermined value.

With this configuration, the workpiece conveying apparatus can be adjusted to form a workpiece conveying apparatus capable of conveying a workpiece without any obstacle in actual use by the amplitude measuring step and the traveling wave ratio adjusting step.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide a workpiece conveying device capable of suppressing inconsistency in the conveying speed of a workpiece by providing a traveling wave ratio adjusting means for adjusting the traveling wave ratio.

Further, the present invention can provide a workpiece conveying apparatus that can convey a workpiece without any trouble in actual use, even if the generation of a perfect traveling wave is not aimed at. Therefore, the required design accuracy and adjustment accuracy can be relaxed to such an extent that the conveyance of the workpiece is not hindered.

Drawings

Fig. 1 is a perspective view showing a workpiece conveying device (parts feeder) according to a main embodiment of the present invention.

Fig. 2 is an enlarged perspective view of a main portion showing a part of the vibrating tray feeder and the linear feeder of the work conveying apparatus (parts feeder).

Fig. 3 is a block diagram showing the configuration of the workpiece conveying device (parts feeder) according to the main embodiment.

Fig. 4 is a graph for explaining the concept of the traveling wave ratio.

Fig. 5 is a graph showing a relationship between a traveling wave ratio and a natural frequency difference ratio.

Fig. 6 is a block diagram of a workpiece transfer device according to an additional embodiment.

Fig. 7 is a side view of a straight feeder.

Fig. 8 is a bottom view of the inline feeder.

Fig. 9 is a block diagram of a workpiece conveying apparatus according to another embodiment.

Fig. 10 is a flowchart when the workpiece conveying device (parts feeder) is adjusted.

Fig. 11 shows a traveling wave generating unit according to another embodiment, in which (a) is a top view, (b) is a side view, and (c) is a bottom view.

Fig. 12 shows a traveling wave generating unit according to another embodiment, in which (a) is a top view and (b) is a side view.

Description of the reference numerals

1. A workpiece conveying device, a part feeder; 2. a base portion; 3. a vibrating pan feeder; 31. a conveying part and a vibration plate feeder side conveying part; 32. a fixed part (vibration plate feeder); 33. conveying tracks, spiral tracks, tracks; 331. a conveying surface (spiral track); 4. a straight feeder; 41. a conveying part and a side conveying part of a straight feeder; 42. a fixed part (a straight feeder); 43. a conveying rail, a main rail; 431. a conveying surface (main rail); 44. a conveying track and a return track; 441. a conveying surface (return track); 5. a traveling wave generating unit; S1-S3, amplitude measuring step; S3-S9, a traveling wave ratio adjusting step; 5B, group of return side; 5F, group of feed sides; 6A, a biphase alternating current signal transmitter; 7. a rigidity adjusting unit; 34. 35, sewing grooves; 45. slotting; 51. 52, 521, electrodes; 53. 531, a ceramic part; 61. an amplifier; 62. a voltage adjustment unit; 63. an excitation frequency adjusting unit; 64. an electric phase adjustment unit; 65. a waveform selection unit; 71. 72, 73, 74, plate members; 332. an outer peripheral end portion; 414. a conveying section; 611. a 1 st amplifier; 612. a 2 nd amplifier; w, a workpiece.

Detailed Description

The present invention will be described below with reference to the accompanying drawings, taking one embodiment as a main embodiment.

As shown in fig. 1, a parts feeder 1 as a workpiece conveying device of the present embodiment is provided with a disk-shaped vibrating tray feeder 3 and a linear feeder 4 connected to extend radially outward of the vibrating tray feeder 3 on a base portion 2.

The vibrating tray feeder 3 includes a vibrating tray feeder side conveying part 31 as a disk-shaped member. The vibrating plate feeder-side conveying unit 31 is fixed to the base unit 2 by a fixing unit 32 located at the center. In the present embodiment, the fixation is achieved by fastening with one bolt via the circular plate, but the number of bolts is not limited, and fixation by other means may be possible. The upper surface of the vibrating tray feeder-side conveying unit 31 first descends from the center and then ascends toward the peripheral edge as shown in the drawing. The work W to be conveyed can be thrown into the recessed portion of the vibrating tray feeder-side conveying section 31. In the vibrating tray feeder 3, as a conveying path for conveying the workpiece W, a spiral path 33 as a spiral groove is formed on the upper surface of the vibrating tray feeder-side conveying unit 31 from the inner circumferential position to the outer circumferential position of the vibrating tray feeder-side conveying unit 31. The spiral path 33 has a conveying surface 331 which contacts the workpiece W. The conveyance surface 331 is deflected and deformed by the traveling wave generating means 5, and conveys the workpiece W. The outer peripheral end 332 of the spiral rail 33 is formed at a position where the work W can be transferred to the main rail 43 of the linear feeder 4. During the operation of the vibratory pan feeder 3, the workpiece W moves on the spiral rail 33 so as to gradually rise as indicated by arrows in fig. 2, and is transferred from the outer peripheral end 332, which is the downstream end in the conveying direction of the workpiece W, to the main rail 43.

The linear feeder 4 includes a linear feeder side conveying unit 41 having a rectangular shape in plan view. The linear feeder side conveying unit 41 is fixed to the base unit 2 by a fixing unit 42 located at the center in the width direction. In the present embodiment, the fixing is achieved by fastening a plurality of bolts, but the fixing may be achieved by other means. The conveying rail of the inline feeder 4 includes a main rail 43 and a return rail 44. The main rail 43 has a linear groove extending in the longitudinal direction on the feeding side of the upper surface of the linear feeder side conveying unit 41. The return rail 44 has a U-shaped groove as a whole, which is a linear groove extending in the longitudinal direction on one side in the width direction (hereinafter referred to as the "feed side") and the other side in the width direction (hereinafter referred to as the "return side") of the upper surface of the linear feeder side conveying part 41, and a curved groove connecting the grooves in the vicinity of the end portion of the linear feeder 4 on the side away from the vibrating tray feeder 3. The return-side groove is connected to the vibrating tray feeder-side conveying section 31. The conveying rail is not limited to such a shape that is closed in a circulating manner, and may be a shape that is open at one end or both ends. The main rail 43 and the return rail 44 have conveying

surfaces

431 and 441 that contact the workpiece W. These conveyance surfaces 431 and 441 are deflected and deformed by the traveling wave generating means 5, and convey the workpiece W.

In the present embodiment, the main rail 43 and a part of the return rail 44 are formed in parallel, and the workpiece W to be returned from the main rail 43 to the vibratory pan feeder 3 is moved by a moving unit (air nozzle or the like) not shown, and is changed from the main rail 43 to the return rail 44.

In this manner, the vibrating pan feeder 3 and the linear feeder 4 are formed in a shape circulating around the fixing

portions

32 and 42, and at least some of the portions having the shape are formed as conveying portions (the vibrating pan feeder-side conveying portion 31 and the linear feeder-side conveying portion 41) serving as conveying

surfaces

331, 431, and 441 for conveying the workpiece W in a state where the workpiece W is placed thereon. Each of the conveying

portions

31 and 41 has elasticity to such an extent that it can be deformed by the later-described traveling wave generating means 5. The "circular shape" does not mean a shape in which the conveyance surfaces 331, 431, 441 and the conveyance tracks 33, 43, 44 continuously rotate one round, but means a shape in which a traveling wave is generated and a partial circulation is performed. Therefore, the circular vibrating tray feeder-side conveying unit 31 naturally conforms to the "circular shape", and the straight feeder-side conveying unit 41 having a long circular region around the fixing unit 42 also conforms to the "circular shape".

The vibrating pan feeder 3 and the linear feeder 4 include a traveling wave generating unit 5, and the traveling wave generating unit 5 generates a traveling wave that travels in the circulation direction on each of the conveying

surfaces

331, 431, 441 by bending and elastically vibrating the conveying

surfaces

331, 431, 441 in a fluctuating manner (see fig. 3 for the linear feeder 4). The traveling wave generating means 5 of the present embodiment is driven at a frequency in the ultrasonic range (specifically, 20kHz or more). As a specific example of the traveling wave generating means 5, a piezoelectric element that expands and contracts or bends and deforms when energized can be exemplified, and other members such as a vibrator, an eccentric motor, and a solenoid that exhibit various operations when energized can be used. The traveling wave generating unit 5 is provided on the back side of the vibrating pan feeder-side conveying unit 31 and the straight feeder-side conveying unit 41, that is, on the side opposite to the side on which the conveying

surfaces

331, 431, 441 are formed.

In the linear feeder 4, as schematically shown in fig. 3, two sets of the feed-side group 5F and the return-side group 5B having different output phases are arranged at different positions in the circulating direction (workpiece conveying direction) of the linear feeder-side conveying unit 41 and are arranged in the longitudinal direction of the linear feeder-side conveying unit 5. In fig. 3, 4 traveling-wave generating units 5 are shown in each group, but the number of traveling-wave generating units 5 is not limited thereto. The plurality of traveling-wave generating units 5 belonging to each

group

5F, 5B are arranged at 1/2-wavelength intervals at the antinodes of the vibration mode (waveform) and with the polarities of the adjacent traveling-wave generating units 5 (shown as "+", "-") reversed. Thereby, the traveling wave generating units 5 belonging to the feeding-side group 5F form an excitation region (1 st excitation region) on the feeding side, and the traveling wave generating units 5 belonging to the returning-side group 5B form an excitation region (2 nd excitation region) on the returning side. In the linear feeder 4, the traveling wave generating units 5 belonging to the feed-side group 5F and the traveling wave generating units 5 belonging to the return-side group 5B are arranged so as to be shifted by 1/4 wavelengths (shown as "λ/4") in the longitudinal direction of the linear feeder-side conveying unit 41. As shown in fig. 3, the traveling-wave generating units 5 belonging to the feed-side group 5F are connected to the 1 st amplifier 611, and the traveling-wave generating units 5 belonging to the return-side group 5B are connected to the 2 nd amplifier 612. The 1 st amplifier 611 is connected to the 1 st amplitude adjustment unit 621. The 2 nd amplifier 612 is connected to a 2 nd amplitude adjustment unit 622. The 1 st amplitude adjusting section 621 is connected to the excitation frequency adjusting section 63. The 2 nd amplitude adjusting section 622 is connected to the excitation frequency adjusting section 63 via the electrical phase adjusting section 64. The excitation frequency adjusting means 63 is connected to the waveform selecting means 65. In the present embodiment, the 1 st amplitude adjusting section 621, the 2 nd amplitude adjusting section 622, the excitation frequency adjusting section 63, the electrical phase adjusting section 64, and the waveform selecting section 65 are integrally formed to constitute the signal transmitter 6A.

Sinusoidal wave vibrations with a phase shift of 90 ° in time can be generated by the forward wave generating means 5 on the feed side and the forward wave generating means 5 on the return side by the electric phase adjusting means 64. In the present embodiment, the excitation mode generated by the 1 st amplifier 611 is a "90 ° mode", and the excitation mode generated by the 2 nd amplifier 612 is a "0 ° mode".

Although not shown, the vibrating pan feeder 3 is similar in that the relationship between the one half-circumference portion and the other half-circumference portion is similar to the feeding side and the returning side of the linear feeder 4 with respect to the center of the vibrating pan feeder side conveying unit 31.

Each line wave generating unit 5 is driven, and thereby each of the conveying

surfaces

331, 431, 441 can be wavedly deflected and elastically vibrated. Here, with the above-described configuration, sinusoidal wave vibrations with a phase shifted by 90 ° in time can be generated by the traveling wave generation means 5 on the feed side and the traveling wave generation means 5 on the return side. Therefore, the standing waves (waves that vibrate only vertically at a certain position) generated in the respective conveying

units

31 and 41 overlap spatially and temporally, and thus the respective conveying

surfaces

331, 431, and 441 can generate traveling waves that travel in the circulating direction of the vibrating tray feeder 3 and the linear feeder 4. The traveling wave of the present embodiment travels counterclockwise in plan view. In the parts feeder 1 of the present embodiment, the traveling waves are generated on the respective conveying

surfaces

331, 431, 441 such that the amplitudes at the different positions in the circulating direction of the respective conveying

sections

31, 41 are not perfectly uniform, but are different (in magnitude) in the amplitude at the different positions in the circulating direction.

One point on each of the transport surfaces 331, 431, 441, which is generating the traveling wave, generates an elliptical motion. The moving direction of the elliptical motion is opposite to the traveling direction of the traveling wave at the top of the locus of the elliptical motion. Then, due to the friction between the conveying

surfaces

331, 431, 441 and the workpiece W, a thrust force is generated on the workpiece W on the conveying

surfaces

331, 431, 441, and the workpiece W is conveyed in the direction opposite to the traveling wave.

A plurality of

slits

34, 45 are formed at predetermined intervals in the upper portion of each of the conveying

sections

31, 41 in the present embodiment. The slit 34 of the vibratory pan feeder 3 is formed to extend in the radial direction, and the slit 45 of the linear feeder 4 is formed to extend in the width direction. By forming these

slits

34 and 45, the neutral axis (an imaginary axis that becomes a bending center when each of the conveying

sections

31 and 41 is bent) is located downward, and the conveying

sections

31 and 41 are easily deformed in the traveling direction of the traveling wave, and the ellipse of the elliptical motion can be deformed into a horizontally long shape. Therefore, the horizontal component of the force acting on the workpiece W increases, and the vertical component decreases. Therefore, compared to the case of using a conveying unit without forming the

slits

34 and 45, the workpiece W can be efficiently moved at an increased conveying speed without jumping up on the conveying surface.

In the parts feeder 1 of the present embodiment configured as described above, a perfect traveling wave is not present on each of the conveying

surfaces

331, 431, 441, but a traveling wave having a difference (in magnitude) in amplitude at different positions in the circulating direction of each of the conveying

units

31, 41 is generated. Therefore, the conveying

surfaces

331, 431, 441 alternately assume a position where the amplitude is large (the waveform is shown as "maximum time" in fig. 4) and a position where the amplitude is small (the waveform is shown as "minimum time" in fig. 4). In the present embodiment, the traveling wave ratio is set to 0.13 or more, and the traveling wave ratio is defined as a ratio of a minimum amplitude at a position where vibration of each of the transport surfaces 331, 431, 441 is minimum within a predetermined range to a maximum amplitude at a position where vibration is maximum within the predetermined range, among vertical amplitudes of the transport surfaces 331, 431, 441 due to the traveling wave. The set value is preferably set to 0.20 or more, and more preferably 0.25 or more. In addition, the traveling wave ratio when the respective conveyance surfaces 331, 431, 441 present perfect traveling waves is 1. Further, the degree of difficulty in jumping up the workpiece W on the conveying surface varies depending on the quality of the workpiece W. The jumping of the work W becomes a factor that hinders smooth conveyance of the work W. Therefore, the set traveling wave ratio is conditioned by adjusting the amplitude by the 1 st amplitude adjusting means 621 and the 2 nd amplitude adjusting means 622 to suppress the jump of the workpiece W on the conveying surface.

The natural frequencies of the 0 ° mode and the 90 ° mode are different values from each other. Regarding the difference in natural frequency, the natural frequency difference ratio (Δ f), which is the ratio of the difference between the natural frequency (f2) and the natural frequency (f1) to the natural frequency (f1), is expressed by the following equation. Δ f ═ (f 2-f 1)/f1 × 100 (wherein f2 > f1)

Fig. 5 shows a relationship between the traveling wave ratio and the natural frequency difference ratio Δ f. The horizontal axis (natural frequency difference ratio Δ f) of the graph of fig. 5 is expressed in percentage (%). From the above equation and fig. 5, it can be seen that: the value of the natural frequency difference ratio Δ f having a traveling wave ratio of 0.13 or more described in the present embodiment is the natural frequency difference ratio Δ f ≦ 1.54. Therefore, if the natural frequency difference ratio Δ f is less than or equal to 1.54, the workpiece conveying device (parts feeder 1) capable of conveying the workpiece W without any trouble in actual use can be formed.

Here, the inventors of the present application confirmed the conveyance smoothness of the workpiece W by experiments. The workpiece W to be tested was a plate-like body having a size of 3.2mm × 1.6mm, a thickness of 1.6mm, and a weight of about 50mg, and specifically, was a chip capacitor having a ceramic plate on which metal electrodes were mounted. The experiment was carried out using a straight feeder 4. Based on the conditions shown in table 1, the observer visually observes the moving state of the workpiece W conveyed on the main rail 43 of the inline feeder 4. The evaluation was: the case where the workpiece W is stopped in the middle of the main rail 43 is denoted by "x", the case where the moving speed is not constant is denoted by "Δ", and the case where the workpiece W is smoothly moved without delay is denoted by "o". The experiment was performed in eight modes with varying traveling wave ratios.

[ TABLE 1 ]

O: fluency, Δ: speed is not constant, x: stopping halfway

In table 1, the traveling wave ratio is represented by an average value and a minimum value (a value obtained by dividing the minimum amplitude value by the maximum amplitude value). The average value is an average value of the traveling wave ratios of a plurality of measurement regions (in the present experiment, 4 regions each obtained by dividing the feed side and the return side into two on the upstream side and the downstream side) in relation to the measurement of the vertical amplitude of the conveying surface 431 of the main rail 43. The minimum value is a minimum value of the traveling wave ratios of the plurality of measurement regions.

The results of the experiment confirmed that: when a plurality of workpieces W are arranged and conveyed, and evaluated by the minimum value of the traveling wave ratio along the main rail 43, the conveyance can be performed smoothly if the value is 0.13 or more. That is, the transport limit traveling wave ratio is 0.13. In addition, it was confirmed that: when the workpiece W is conveyed individually, if the minimum value of the traveling wave ratio along the main rail 43 is used for evaluation, the conveyance can be performed smoothly if the value is 0.20 or more. Further, it is presumed that the reason why smooth conveyance can be achieved with a small traveling wave ratio when conveying a plurality of workpieces W is that the plurality of workpieces W abut against each other before and after the movement direction, are pushed by the workpiece W behind, and contribute to the movement.

In the case of a perfect traveling wave, the amplitudes of the different positions in the circulation direction of the respective conveying

sections

31, 41 are identical, and therefore the traveling wave ratio is 1. On the other hand, when no traveling wave is generated at all and only a standing wave is generated, the traveling wave ratio is 0 because the minimum amplitude is 0 (node portion of the waveform). Therefore, the traveling wave ratio of 0.13 set as the lowest value (transport limit traveling wave ratio) in the present embodiment can be said to be a relatively loose value because the generation degree of the traveling wave is relatively low with respect to the perfect traveling wave. With such setting, the workpiece W can be efficiently conveyed, and the parts feeder 1 having no problem in actual use can be provided. Therefore, the density (design accuracy, adjustment accuracy) of the mechanism for generating the traveling wave in designing and adjusting the parts feeder 1 can be relaxed, and as a result, the manufacturing cost of the parts feeder 1 may be reduced.

The output of the traveling wave ratio can be adjusted by electrically operating the traveling wave generating unit 5. The electrical operation is an operation of changing at least one of the phase difference, the amplitude ratio, and the excitation frequency by an adjustment unit connected to the traveling wave generation unit 5 (more specifically, connected to the 1 st amplifier 611 and the 2 nd amplifier 612 that drive the traveling wave generation unit 5), for example. Specifically, the operation is performed to change at least one of the phase difference between the traveling-wave generating unit 5 to which the feeding-side group 5F belongs and the traveling-wave generating unit 5 to which the returning-side group 5B belongs, the amplitude ratio between the traveling-wave generating unit 5 to which the feeding-side group 5F belongs and the traveling-wave generating unit 5 to which the returning-side group 5B belongs, and the excitation frequency of all the traveling-wave generating units 5. Since the traveling wave ratio can be adjusted by changing any one of the phase difference, the amplitude ratio, and the excitation frequency, a change target suitable for adjustment can be selected according to the situation, and the degree of freedom of adjustment is improved.

The specific adjusting means of the present embodiment are the 1 st amplitude adjusting means 621 and the 2 nd amplitude adjusting means 622, the excitation frequency adjusting means 63, and the electrical phase adjusting means 64 shown in fig. 3. The phase difference can be adjusted by the electric phase adjusting unit 64. The amplitude ratio can be adjusted by the 1 st amplitude adjusting unit 621 and the 2 nd amplitude adjusting unit 622. The excitation frequency can be adjusted by the excitation frequency adjusting unit 63. Further, in the present embodiment, the waveform can be adjusted by the waveform selecting means 65. Since the adjustment of these adjusting means is sufficient by an electric operation, it is advantageous to easily adjust the adjusting means as compared with a case where the configuration of the parts feeder 1 is physically changed.

The traveling wave ratio can be adjusted by changing the generation state of the traveling waves generated by the respective conveying

units

31 and 41 by physically changing the configurations of the respective conveying

units

31 and 41. As for the physical change, the changed configuration can be continued as long as the changed configuration is not changed again, and therefore, there can be cited, as relative advantages: the adjustment can be performed with higher stability than the adjustment performed by the electrical operation that may cause the change reset due to a power failure or the like. Specifically, the adjustment can be performed by attaching an adjustment member to a part of each of the conveying

units

31 and 41. The adjustment member may be, for example, a plate-like body (adjustment plate), but is not limited to the shape. The mounting position of the adjustment member in each of the conveying

units

31 and 41 may be, for example, a back surface, but is not particularly limited. The adjustment member may be attached to a plurality of members at different positions, or may be attached to a plurality of members at the same position in an overlapping manner. The mounting form can be various forms such as adhesion with an adhesive or the like, screwing, fitting, welding, and the like. In addition, the following configuration may be adopted in reverse to the above configuration: the adjustment member is initially removably attached in advance, and removed as needed.

Additional embodiments of the present invention will be described below with reference to the drawings. In the following description, the same reference numerals are given to the same or corresponding parts as those of the main embodiment, and the description thereof will be omitted.

In the explanation of the traveling wave generating means provided in the straight feeder side conveying section 41 among the traveling wave generating means provided on the back sides of the vibrating pan feeder side conveying section 31 and the straight feeder side conveying section 41, as shown in fig. 6, two sets of the group 5F on the feed side and the group 5B on the return side, which output different phases, are respectively located at different positions in the circulating direction of the straight feeder side conveying section 41 in the plurality of traveling wave generating means 5, and are arranged in the longitudinal direction. In fig. 6, for convenience of explanation, 4 traveling wave generating means 5 are described for each group, but actually, 8 traveling wave generating means 5 are provided for each group on the back side of the linear feeder side conveying unit 41 as shown in fig. 8. The number of the traveling wave generating units 5 is determined according to the size of the linear feeder side conveying unit 41, the set workpiece conveying speed, and the like. Returning to fig. 6, the plurality of traveling-wave generating units 5 belonging to each

group

5F, 5B are arranged at 1/2-wavelength intervals at the antinodes of the vibration mode and with the polarities (shown "+" and "-") of the adjacent traveling-wave generating units 5 reversed. In the linear feeder 4, the traveling wave generating units 5 provided on the feed side and the traveling wave generating units 5 provided on the return side are arranged in a state of having a spatial phase difference of 1/4 wavelengths (shown as "λ/4") in the longitudinal direction of the linear feeder side conveying unit 41. As shown in fig. 6, the traveling-wave generating units 5 belonging to the feed-side group 5F are connected to the 1 st amplifier 611, and the traveling-wave generating units 5 belonging to the return-side group 5B are connected to the 2 nd amplifier 612. The 1 st amplifier 611 and the 2 nd amplifier 612 are connected to a two-phase ac signal transmitter 6A for supplying a two-phase ac signal.

Sinusoidal wave vibrations with a phase shift of 90 ° in time can be generated by the traveling-wave generating unit 5 on the feed side and the traveling-wave generating unit 5 on the return side by the two-phase ac signal transmitter 6A. In the present embodiment, the excitation mode generated by the 1 st amplifier 611 is a "90 ° mode", and the excitation mode generated by the 2 nd amplifier 612 is a "0 ° mode".

Each of the transport surfaces 431 and 441 can be oscillated by each line wave generating means 5. Here, with the above-described configuration, sinusoidal wave vibrations with a phase shifted by 90 ° in time can be generated by the traveling wave generation means 5 on the feed side and the traveling wave generation means 5 on the return side. Therefore, the two standing waves (waves that vibrate only vertically at a certain position) generated by the conveying

units

31 and 41 and shifted in time in space are superimposed (combined) so that the conveying

surfaces

431 and 441 generate traveling waves that travel in the circulating direction on the vibrating tray feeder 3 and the linear feeder 4. The traveling wave of the present embodiment travels counterclockwise in plan view. In the parts feeder 1 of the present embodiment, a perfect traveling wave is not present on each of the conveying

surfaces

431 and 441, but a traveling wave whose amplitude varies at different positions on the conveying surface is present. This is not only because the two

conveyance surfaces

431 and 441 cannot be formed in a completely symmetrical shape, but also because the mounting position of the traveling wave generating unit 5 (piezoelectric element in this case) and the driving state of the traveling wave generating unit 5 (piezoelectric element in this case) are different.

A point on each of the transport surfaces 431, 441, which is generating a traveling wave, generates an elliptical motion. The direction of motion of this elliptical motion is opposite to the direction of travel of the traveling wave at the top. Then, due to friction between the conveying

surfaces

431 and 441 and the workpiece W, a thrust force is generated on the workpiece W on the conveying

surfaces

431 and 441, and the workpiece W is conveyed in a direction opposite to the traveling wave.

Although not shown, the vibrating pan feeder 3 is similar in structure, the relationship between one half-circumference portion and the other half-circumference portion across the center of the vibrating pan feeder side conveying unit 31 is similar to the relationship between the feeding side and the returning side of the linear feeder 4, and the traveling wave generating means is arranged and driven in the same manner as in the case of the linear feeder 4.

A plurality of

slits

sections

slits

34 and 45, the neutral axis (an imaginary axis that becomes the bending center when the conveying

sections

31 and 41 are bent) is located downward, and the conveying

sections

31 and 41 are easily deformed in the traveling direction of the traveling wave, and the ellipse of the elliptical motion can be deformed to be horizontally long. Therefore, the horizontal component of the force acting on the workpiece W increases, and the vertical component decreases. Therefore, the workpiece W can be moved efficiently without jumping up, as compared with the case of using a conveying unit in which no slit is formed.

In the parts feeder 1 of the present embodiment configured as described above, the traveling waves that vary in amplitude at different positions on the conveying surface are not perfectly present on the conveying

surfaces

331, 431, 441. Therefore, the conveying

surfaces

331, 431, 441 alternately assume a position where the amplitude is large (the waveform is shown as "maximum time" in fig. 4) and a position where the amplitude is small (the waveform is shown as "minimum time" in fig. 4). Therefore, a traveling wave ratio adjusting means for adjusting a traveling wave ratio defined as a ratio of a minimum amplitude at a position where vibration is minimum to a maximum amplitude at a position where vibration is maximum among vertical amplitudes of the conveying

surfaces

331, 431, 441 due to the traveling wave is provided, and the traveling wave ratio is the minimum amplitude/the maximum amplitude. A perfect traveling wave is formed when the two-phase standing wave is a standing wave whose phase difference in space and phase difference in time are both 90 degrees and whose amplitude is equal.

The traveling wave ratio is 1 in the case of a perfect traveling wave, and is 0 in the case of a standing wave alone without a traveling wave at all. Therefore, the adjustment is performed by the traveling wave ratio adjusting means so that the traveling wave ratio approaches 1. The traveling wave ratio adjusting means may include at least one of means for adjusting the rigidity of the specific portion of the conveying

section

31, 41, means for increasing or decreasing the mass of the specific portion of the conveying

section

31, 41, and means for adjusting the damping characteristics of the vibration of the conveying

surface

331, 431, 441.

Fig. 7 and 8 show the rigidity adjusting means 7 for adjusting the rigidity of a specific portion of the straight feeder side conveying unit 41 of the conveying

units

31 and 41. In fig. 7 and 8, the rigidity adjusting means 7 is configured by 4

plate members

71, 72, 73, and 74 attached to the conveying section 41 so as not to overlap with the traveling wave generating means (piezoelectric element) 5. Here, the 4

plate members

71, 72, 73, and 74 are attached to the conveying unit 41 by an adhesive, screws, or the like.

The 4

plate members

71, 72, 73, and 74 are attached to the conveying unit 41 at positions other than the workpiece passage portion, and are configured to be elastically deformable together with the conveying unit 41. Specifically, the 4

plate members

71, 72, 73, and 74 are attached to the back surface of the conveying unit 41. 8 traveling wave generating units (piezoelectric elements) 5 are disposed at both ends of the back surface of the transport unit 41 in the width direction (the short side direction of the transport unit 41), and the 8 traveling wave generating units 5 are disposed in a state where a phase difference of a space having a wavelength of 1/4 is present in the longitudinal direction of the linear feeder side transport unit 41. The

plate members

71, 72, 73, and 74 are attached to four locations, namely, both ends in the width direction of the linear feeder side conveying unit 41 where the 8 traveling wave generating units (piezoelectric elements) 5 are not attached and both ends in the length direction of the conveying unit 41. By mounting the 4

plate members

71, 72, 73, 74, the rigidity of the mounting portion is improved. As a result, the amplitude at the mounting portion changes, and the vibration characteristics of the specific portion of the linear feeder side conveying unit 41 change, and the traveling wave ratio can be adjusted. In particular, the

plate members

71, 72, 73, and 74 are mounted on the portions corresponding to the antinodes of the standing wave, so that the vibration characteristics are largely changed.

The

plate members

71, 72, 73, and 74 are formed to have substantially the same width and substantially the same thickness as the traveling wave generating unit (piezoelectric element) 5, but the width and thickness of the

plate members

71, 72, 73, and 74 may be set so that the rigidity of the straight feeder side conveying part 41 is substantially the same at any portion. Among the 4

sheet members

71, 72, 73, 74, the length of the

sheet members

71, 72 attached to one end side in the width direction of the linear feeder side conveying unit 41 is substantially the same as the length of the

sheet members

73, 74 attached to the other end side in the width direction of the linear feeder side conveying unit 41, and therefore, the rigidity of one end in the width direction of the linear feeder side conveying unit 41 and the rigidity of the other end in the width direction are easily matched. The

plate members

71, 72, 73, and 74 may be made of the same material (the same material) as the traveling-wave generation unit (piezoelectric element) 5, although they may be elastically deformed by the traveling wave in the same manner as the transport unit if they are made of the same metal (for example, aluminum) as the material of the linear feeder side transport unit 41. Further, a plate member may be attached to a specific portion of the vibrating tray feeder-side conveying unit 31, and the amplitude of the vibration at the attached portion may be changed, so that the vibration characteristics of the specific portion of the vibrating tray feeder-side conveying unit 31 may be changed, and the traveling wave ratio may be adjusted. Here, the plate member is attached to the back surface of the conveying section, but may be attached to the side surface of the conveying section.

As means for increasing or decreasing the mass of the specific portion of the conveying section 31, for example, means for adding a spindle to the specific portion of the conveying

section

31 or 41 may be included. That is, a part of the back surface of the conveying

sections

31 and 41 is stuck or hung with a spindle. Thus, the weight of the conveying

units

31 and 41 is adjusted to be locally increased, and the vibration characteristics of the specific portions of the conveying

units

31 and 41 are changed, whereby the traveling wave ratio can be adjusted. Further, for example, the conveying

portions

31 and 41 may be cut to reduce the thickness of the conveying

portions

31 and 41, thereby reducing the mass of a specific portion of the conveying portion 31.

Examples of the means for adjusting the damping characteristics of the vibrations of the conveying

surfaces

331, 431, 441 include means for changing the damping characteristics by attaching dampers to the conveying

portions

31, 41. This changes the vibration characteristics of the specific portions of the conveying

units

31 and 41, and the traveling wave ratio can be adjusted.

Further, the travelling wave ratio may be adjusted by changing the vibration characteristics of a specific portion of the conveying

units

31 and 41 by detaching some of the fixing

portions

32 and 42 for fixing the conveying

units

31 and 41 or adjusting the fastening force of some or all of the fixing

portions

32 and 42.

In addition, the traveling wave ratio can also be adjusted from an electrical perspective. For example, as shown in fig. 9, each line wave generating unit 5 belonging to the group 5F on the feed side is connected in series to the amplifier 61 and the voltage adjusting unit 62, and each line wave generating unit 5 belonging to the group 5B on the return side is also connected in series to the amplifier 61 and the voltage adjusting unit 62. Thus, the voltage of the voltage adjusting unit 62 is adjusted, thereby adjusting the traveling wave ratio from an electrical perspective. The feeding-side voltage adjusting means 62 is connected to the excitation frequency adjusting means 63. The return-side voltage adjusting means 62 is connected to the excitation frequency adjusting means 63 via the electrical phase adjusting means 64. The excitation frequency adjusting means 63 is connected to the waveform selecting means 65.

Next, the method of adjusting the parts feeder 1 according to the present embodiment will be described together with the flowchart (fig. 10). First, an amplitude measurement step (corresponding to steps S1 to S3 shown in fig. 10) is performed in which the vertical amplitude is measured at a plurality of positions in the circulation direction (workpiece conveyance direction) of each

conveyance surface

331, 431, 441. More specifically, the amplitude measurement step is performed in the following order. First, the natural frequencies (f1, f2) of the 0 ° wave mode and the 90 ° wave mode are measured (step S1). The measurement of the natural frequency is performed by: the 0 ° wave pattern and the 90 ° wave pattern are individually driven, and frequencies at which the amplitudes of certain points (the positions of antinodes of the wave patterns) on the transport surfaces 331, 431, 441 become maximum are searched for while changing the frequencies for the respective wave patterns. The explored frequency is a natural frequency. Then, the excitation frequency is set to the intermediate value between the measured values of the natural frequency, the amplitude ratio is set to 1, the electrical phase is set to 90 °, and vibration is applied to the parts feeder 1 (step S2). Then, each of the conveying

units

31 and 41 is divided into a plurality of measurement regions, and the vertical amplitude is measured in each measurement region to obtain a traveling wave ratio (step S3). The measurement of the vertical amplitude is carried out by: the measurement unit is scanned above the conveyance rail in each area in the conveyance direction of the workpiece W, and measurements are performed at a plurality of positions. In the present embodiment, a doppler vibrometer is used as the measurement means, but the present invention is not limited thereto, and various tools capable of measuring vibration can be used.

Next, a line wave ratio adjustment step of adjusting the line wave ratio obtained in the amplitude measurement step to a predetermined value is performed (corresponding to steps S3 (in a loop) to S9 shown in fig. 10). More specifically, the traveling wave ratio adjusting step is performed in the following order.

First, it is determined whether or not the minimum value of the Traveling Wave Ratios (TWR) in the measurement regions is 0.13 or more which is a conveyance limit traveling wave ratio (step S4). If the value is 0.13 or more ("Y" in the flowchart), the adjustment is ended. Otherwise ("N" in the flowchart), the electrical phase adjusting unit 64 is operated to change the electrical phase difference (step S5). After the change, the process returns to step S3.

If the desired adjustment cannot be achieved only by changing the electrical phase difference (for example, if the number of times of repetition of steps S3 to S5 is equal to or greater than a predetermined number of times), the 1 st amplitude adjusting means 621 and the 2 nd amplitude adjusting means 622 are operated to change the amplitude ratio (step S6). After the change, the process returns to step S3.

If the desired adjustment cannot be achieved only by changing the electrical phase difference and the amplitude ratio (for example, if the number of repetitions of steps S3 to S6 is equal to or greater than a predetermined number of times), the excitation frequency adjusting means 63 is operated to change the excitation frequency (step S7). The excitation frequency is changed in a range in which the range of the natural frequency of the 0 ° mode and the range of the natural frequency of the 90 ° mode are expanded inward and outward by, for example, 1%. After the change, the process returns to step S3.

If the desired adjustment cannot be achieved even by changing the electrical phase difference, the amplitude ratio, or the excitation frequency (for example, if the number of repetitions of steps S3 to S7 is equal to or greater than a predetermined number of times), the number of times of the vibration mode is changed (step S8). The number of vibration modes is changed as follows: the frequency is changed to a large extent beyond the range of frequency change in step S7, and vibration is applied in a vibration mode (natural frequency) in which the wave number (wavelength) changes. After the change, the process returns to step S3.

If the desired adjustment cannot be achieved even by changing the electrical phase difference, the amplitude ratio, the excitation frequency, or the number of times of the vibration mode (for example, if the number of times of repetition of steps S3 to S8 becomes equal to or more than a predetermined number of times), the adjustment of the traveling wave ratio by the electrically operated traveling wave generating means 5 is abandoned. In this case, the traveling wave ratio is adjusted by physically changing the configuration of each of the conveying units 31 and 41 (step S9). For example, the vibration state of a part of each of the conveying

units

31 and 41 is changed by attaching an adjustment plate to the back surface of each of the conveying

units

31 and 41.

In this way, the adjustment can be made by the amplitude measuring step and the traveling wave ratio adjusting step to form the parts feeder 1 capable of conveying the workpiece W without any trouble in actual use.

The present invention has been described above by way of the embodiments, but the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the present invention.

The traveling wave generation means (piezoelectric element) 5 of the above embodiment includes a ceramic portion as an insulator for electrical insulation and electrodes formed on both side surfaces of the ceramic portion, and normally, piezoelectric elements each having electrodes bonded to both side surfaces of 1 ceramic portion are bonded to the transport portion in a required number, but may be configured and implemented as shown in fig. 11 (a), (b), and (c). That is, the piezoelectric element 5 in which the ceramic portion 531 is integrally formed may be used. In this case, as shown by "+" and "-" in fig. 11 (a), the polarization direction is different for each 1/2 wavelengths (λ/2). Further, the electrode 52 on the opposite side of the electrode 51 on the bonding surface side to be bonded to the transport section (conductor) is integrated with the both side surfaces of the ceramic section 531. Thus, the accuracy of the adhesion of the

electrodes

51 and 52 to the ceramic portion 531 can be improved, and the common operation of the electrode 52 on the opposite side can be reduced. In addition, since the plurality of (8 in the figure) electrodes 51 attached to the transport unit (conductor) are electrically connected to the transport unit to form a common electrode when attached to the transport unit (conductor), a common operation is not necessary. Further, a plurality of (8 in the figure) electrodes 51 on the side of the bonding surface to be bonded to the conveying section (conductor) may be integrated. However, since the step of integrating the plurality of (8 in the figure) electrodes 51 is a step after the plurality of (8 in the figure) electrodes 51 are produced, it is advantageous to integrate only the electrode 52 on the side opposite to the bonding surface of the conveying section as shown in (a), (b), and (c) of fig. 11 in view of reducing the production cost.

The traveling wave generation means (piezoelectric element) 5 of the above embodiment may be configured as shown in fig. 12 (a) and (b). That is, the piezoelectric element 5 in which the ceramic portion 531 is integrally formed may be used as in (a), (b), and (c) of fig. 11. In this case, as shown by "+" and "-" in fig. 12 (a), the polarization direction is different for each 1/2 wavelengths (λ/2). Thus, the accuracy of the adhesion of the

electrodes

51 and 52 to the ceramic portion 531 can be improved. In this case, the plurality of (8 in the figure) electrodes 51 attached to the conveying unit (conductor) are electrically connected to the conveying unit to form a common electrode when attached to the conveying unit (conductor), and therefore, a common operation is not necessary, but a common operation is necessary for the plurality of (8 in the figure) electrodes 521 on the opposite side of the electrodes 51.

In the above embodiment, the plurality of traveling wave generating means 5 are divided into two groups, and the phase difference (phase difference indicating the traveling wave generating means 5) driven by one group and the other group is set to 90 °, but the present invention is not limited thereto, and the phase difference may be set to another angle. Further, the plurality of traveling wave generating means 5 may be divided into 3 or more groups.

In the above embodiment, the traveling wave generating units 5 belonging to the feed-side group 5F are connected to the 1 st amplifier 611 and the 1 st amplitude adjusting unit 621, and the traveling wave generating units 5 belonging to the return-side group 5B are connected to the 2 nd amplifier 612 and the 2 nd amplitude adjusting unit 622. However, in addition to this, an amplifier and an amplitude adjusting means may be connected to each traveling wave generating means 5 of the plurality of traveling wave generating means 5, and the traveling wave ratio may be adjusted by operating each amplitude adjusting means.

In the above-described embodiment, the wave of the vibration generated on the transport surfaces 331, 431, 441 by the traveling-wave generating means 5 is a sine wave in the above-described embodiment, but may be a wave having another shape such as a rectangular wave or a triangular wave.

Further, the respective conveying

portions

31 and 41 of the present embodiment are formed in a circular shape, but the shape of the conveying portions is not limited thereto, and may be a straight line shape or a curved line shape that does not circulate once.

In the above-described embodiment, the plurality of traveling-wave generating units 5 are arranged in the respective conveying

sections

31 and 41, but the present invention is not limited to this, and, for example, a traveling wave may be generated by applying vibration with a phase difference only to both ends of the conveying section elastically supported, or by applying vibration to one end and absorbing vibration at the other end.

As another means for adjusting the rigidity of the specific portion of the conveying

unit

31, 41, a spring may be additionally provided to adjust the rigidity of the specific portion of the conveying unit.

Claims

1. A workpiece transport apparatus comprising:

a conveying section having a conveying surface for conveying the workpiece in a state where the workpiece is placed, the conveying section being elastically deformable; and

a traveling wave generation means for generating a traveling wave on at least the transport surface by combining two standing waves generated by driving the traveling wave generation means at different phases,

when the traveling wave is generated under the condition that the amplitude of the traveling wave may vary at different positions of the conveying surface, positions with large amplitude and positions with small amplitude are alternately presented on the conveying surface,

the workpiece conveying apparatus further includes a traveling wave ratio adjusting means for adjusting a traveling wave ratio, which is a ratio of a minimum amplitude at a position where vibration of the traveling wave is minimum to a maximum amplitude at a position where vibration is maximum, among amplitudes generated on the conveying surface.

2. The workpiece conveying apparatus according to claim 1,

the traveling wave ratio adjusting means is configured to adjust the traveling wave ratio to 0.13 or more.

3. The workpiece conveying apparatus according to claim 1 or 2,

adjusting an output of the traveling wave ratio by electrically operating the traveling wave generating unit.

4. The workpiece conveying apparatus according to claim 3,

the traveling wave generating means is divided into at least two groups having different output phases and arranged at different positions in the workpiece conveying direction of the conveying section,

the electrical operation of the traveling wave generation unit is an operation of changing at least one of a phase difference between the traveling wave generation unit to which one of the at least two groups belongs and the traveling wave generation unit to which the other group belongs, an amplitude ratio between the traveling wave generation unit to which the one group belongs and the traveling wave generation unit to which the other group belongs, and an excitation frequency of all the traveling wave generation units.

5. The workpiece conveying apparatus according to claim 1 or 2,

the traveling wave ratio adjusting means includes at least one of means for adjusting the rigidity of the specific portion of the conveying section, means for adjusting the mass of the specific portion of the conveying section, and means for adjusting the damping characteristics of the vibration of the specific portion of the conveying surface.

6. The workpiece conveying apparatus according to claim 5,

the means for adjusting the rigidity of the specific portion of the conveying section is attached to a portion of the conveying section other than the workpiece passage portion, and is formed of a member configured to be elastically deformable together with the conveying section.

7. A method for adjusting a workpiece conveying device,

the work conveying apparatus includes:

the method comprises the following steps:

an amplitude measuring step of measuring vertical amplitudes of the conveying surface at a plurality of positions in a workpiece conveying direction of the conveying surface; and

a traveling wave ratio adjusting step of adjusting a traveling wave ratio, which is defined as a ratio of a minimum amplitude at a position where the vibration of the conveying surface is minimum within a predetermined range and a maximum amplitude at a position where the vibration is maximum within the predetermined range, obtained in the amplitude measuring step, to a predetermined value.