JPH0240016Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention is a linear conveyor called a trough type,
The present invention also relates to a parts feeder that vibrates a spiral conveyor provided on the inner wall surface of a cylinder called a bowl type, and mainly conveys small articles to the next process.

``Prior art'' As a vibration source for this type of parts feeder, an electrostrictive vibrator is known to consume less power and make the device more compact. This causes fluctuations in the conveyance speed of the object, which increases when the number of objects in the conveyor decreases and decreases when a new object is supplied into the conveyor.

"Problems to be Solved by the Invention" The present invention aims to eliminate the fluctuations in the transport speed caused by the fluctuations in the total weight of the objects to be transported, and to transport the objects at a stable speed.

"Means for solving the problem" It is believed that the above fluctuation in conveyance speed is due to the frequency of the drive voltage of the electrostrictive vibrator being made the same as the natural frequency of the feeder body in order to increase the amplitude. Success was achieved by lowering the frequency of the driving voltage of the vibrator by only 0.5 to 10% below the natural frequency of the latter feeder body.

"Example" FIG. 1 shows a basic form of a trough type as an example of a parts feeder. A diamond-shaped vibration frame 2 is mounted on a grounded and fixed base 1, and a large number of articles P are mounted on the vibration frame 2. The vibration frame 2 has a lower horizontal frame piece 3 fixed to the base 1 and an upper horizontal frame piece 4 that horizontally fixes the trough 6 on the upper surface. They are connected by front and rear inclined plate springs 5, 5, and plate-shaped electrostrictive vibrators 7, 7 are attached to the outer surfaces of these inclined plate springs 5, 5, respectively. The elements 7, 7 are made of a lead zirconate titanate compound, etc., and after forming metallized electrode surfaces (not shown) on both main surfaces by baking silver, etc., they are polarized by a high DC voltage. Lead wires 8, 8 for applying a DC or AC voltage are connected between the respective electrode surfaces. In this case, in the case of DC voltage, a switching mechanism is required to continue energization, whereas in the case of AC voltage at a commercial frequency, it is not necessary.

Here, when an AC voltage is applied to the electrostrictive oscillators 7, 7 to excite them, each oscillator 7, 7 expands in the positive half cycle and contracts in the negative half cycle. The expansion and contraction motion of the electrostrictive vibrator is converted into a bending motion, and the inclined plate springs 5, 5 are vibrated vertically and diagonally using the connecting portion with the lower horizontal frame piece 3 as a fulcrum, and the inclined plate springs 5 are vibrated. , 5, which is fixed on the upper horizontal frame piece 4, is vibrated.

Now, the Young's modulus of leaf spring 5, 5 is 2.1×10 ⁴ Kg/mm.
Select spring steel ^{No. 2} and make its dimensions 63mm long, 25mm wide,
It is 2.3 mm thick, has a mounting angle of 20 degrees, is made of lead zirconate titanate compound, and has a length of 38 mm.
A trough 6 with a length of 135 mm and a width of 135 mm and a width of
It is made of aluminum alloy and has a length of 70mm and a weight of 120g.

On the other hand, the spring constant of the inclined leaf springs 5, 5 and the trough 6
The frequency of the AC voltage applied to the electrostrictive oscillators 7, 7 is determined from the natural frequency of 132 Hz of the parts feeder body, which is determined from the weight of Figure 2 shows the relationship between conveyance speeds when steel is used. However, the AC voltage was fixed at 150V.

In the figure, A shows a case where a voltage with a frequency of 132 Hz, which is the same as the natural frequency of the feeder body, is applied, and B shows a case where a voltage with a lower frequency of 129.5 Hz is applied.

"Effect of the invention" From Figure 2, B
It is clear that the present invention has a great effect because the variation in the conveying speed due to the total weight of the conveyed object is significantly smaller than in A, where the frequency of the drive voltage of the vibrator and the natural frequency of the conveyed body are the same. was made into

Note that how low the frequency of the voltage applied to the electrostrictive vibrator should be relative to the natural frequency of the feeder body varies depending on the weight of the transported object, so it is desirable to determine this in advance through experiments, etc. In the case of the above example, it was confirmed that the best transport efficiency was achieved by lowering the transport efficiency by 90 to 99.5%. Furthermore, although the above embodiments have been described with respect to a trough-type parts feeder, the same effect can be achieved with a bowl-type parts feeder.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a trough-type parts feeder cited as an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the total weight of objects to be conveyed in the trough and the conveyance speed, showing the effects of the present invention. 6...Carrier (trough), 7...Electrostrictive vibrator.

Claims (1)

[Scope of utility model registration request] An electrostrictive vibrating parts feeder characterized in that the frequency of the driving voltage of the electrostrictive vibrator is lower than the natural frequency of the feeder body.