JPH04189215A - Powder material carrying device - Google Patents

Abstract

PURPOSE:To reduce demand and noise, and improve the carrying efficiency by providing oscillation generating means using piezoelectric elements, in which largeness, applying time and applying time of the driving voltage are controlled so as to be different from each other, at multiple positions of the longitudinal direction of a tubular or a chute shape carrying member for carrying the powder material. CONSTITUTION:A powder carrying device consists of a hopper 1, a hollow pipe 2, multiple number of ultrasonic oscillation generating piezoelectric elements 3-1-3-n, and alternating current power sources 4-1-4-n for driving each piezoelectric element. Largeness or applying time or applying period of the voltage of the power sources 4-1-4-n of each piezoelectric element 3-l-3-n are made to be different from each other. For example, applying time and applying period of both piezoelectric elements adjacent to each other are set not to be influenced from each other. Excellent carrying property can be thereby obtained even in the case that oscillation absorption factor of an oscillation absorbing member is low.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a device for conveying powder.

[Prior Art] Conventionally, the most common technique for conveying powder is one using a screw, which is used for all types of powder conveying means. For example, this conveys powder in a pipe by rotating a screw screw installed inside the pipe.

[Problems to be Solved by the Invention] However, in the conventional example described above, since the screw in the pipe must be rotated by a motor, there are problems in that the power consumption is large and the rotation noise is relatively loud.

The configuration also requires a relatively complicated member called a screw and a motor, resulting in a large space and high cost.

Also, if the gap between the screw and the inner wall of the pipe is large, the conveyance efficiency will decrease, and conversely, if the gap between the screw and the inner wall of the pipe is small, the conveyance efficiency will increase, but the friction between the screw and the inner wall of the pipe will increase the rotational torque of the screw. It also had the problem of becoming.

Furthermore, the powder deteriorates due to friction between the inner wall and the screw, etc.
It may break or melt due to frictional heat. In addition, since powder is generally easily charged, the powder often becomes charged during transportation and adheres to the screw, and in severe cases, there is a problem in that transportation may be defective.

The present invention aims to solve the above-mentioned problems and provide a powder conveying device that consumes less power, has less noise, and has good conveying efficiency.

[Means for Solving the Problems] According to the present invention, the above object is as follows: A tubular or trough-like powder conveying member that conveys powder in the longitudinal direction, and a vibrator arranged at a plurality of positions in the longitudinal direction of the member. This is achieved by comprising: a generating means; and a control means for controlling differently the magnitude, application time, or application timing of the driving voltage applied to the L temperature volume vibration generating means.

[Operation] According to the present invention, vibrations are generated in the radial direction of the powder conveying member by the vibration generating means disposed at a plurality of positions in the longitudinal direction of the powder conveying member. Then, traveling waves are generated in both longitudinal directions centering on each vibration generating means. but,
Since the voltage applied to each vibration generating means is different in magnitude, application time, or application timing, interference between traveling waves is prevented. Therefore, the traveling waves generated from each vibration generating means travel in the direction opposite to the direction in which the vibration absorbing member is attached, and the traveling waves are combined. In this way, the powder within the powder conveying member is conveyed in a direction opposite to the direction of the combined traveling wave.

[Example] First to third embodiments of the present invention will be described based on the accompanying drawings.

<First Embodiment> First, FIGS. 1 to 11 regarding the first embodiment of the present invention.
This will be explained using figures.

FIG. 1 shows a first embodiment of the present invention. This device is a powder conveying device according to the present invention.

In FIG. 1, l is a hopper that supplies powder;
2 is an acrylic hollow pipe which is a tubular powder member.

The hollow pipe 2 has an outer diameter of I5-1 and an inner diameter of 10 mm, and extends in the longitudinal direction.

In the longitudinal direction of the hollow pipe 2, ultrasonic vibration generating piezoelectric elements 3 serving as vibration generating means are arranged at regular intervals, and an AC voltage is applied by an AC power source 4.

The piezoelectric element 3 is of a type in which a ceramic PZT having an outer diameter of 30 cm, an inner diameter of 15 cm, and a thickness of 2 cm is sandwiched between electrodes from both sides, as shown in FIG.

By applying a voltage between the electrodes, as shown in Figure 3, expansion and contraction vibrations are excited in the inner and outer diameter directions, that is, in the r direction, due to the expansion and contraction force of the ceramic, and the vibrations are transmitted to the hollow pipe 2 as traveling waves. . The traveling wave generated by the piezoelectric element 3 causes the powder in the hollow pipe to be transported in a direction opposite to the direction of the traveling wave (A in FIG. 1). In addition,
In the above example, the peak-to-peak voltage is 100V, and the frequency is 5.
An alternating current voltage of 0 KHz is applied. This is a value calculated from the resonance mode depending on the shape of the piezoelectric element, and the resonance frequency can be changed by changing the thickness and shape of the piezoelectric element. In addition, in this example, only one piezoelectric element is used, but if a large number of piezoelectric elements are used as a sandwich type (multilayer type) as shown in Fig. 4, the amount of excited vibration will be even larger, and the traveling wave transmitted to the hollow pipe will also be larger. Therefore, the powder conveying force also increases.

Further, as shown in FIG. 5, electrodes may be provided around the circumference of the piezoelectric element. Furthermore, by subdividing the electrodes of the piezoelectric element and changing the polarity of the applied voltage, it is possible to obtain various vibration modes. Specifically, by using the electrode arrangement shown in FIG. 6, it is possible to excite l-axis symmetrical vibration called the ((1,1)) mode shown in FIG.

Furthermore, when the electrode division is further subdivided as shown in FIG. 8, parallel vibration of the central axis called the ((2,1)) mode is excited as shown in FIG. Furthermore, by shifting the phase of the AC voltage applied to these electrodes by 90°, a rotational mode of vibration is also possible.

In this way, many vibration modes can be excited by subdividing the electrodes and shifting the phase of the voltage applied to each electrode. By utilizing these various modes, it is possible to select the optimal excitation mode that matches the characteristics of various powders and obtain sufficient conveying force for each powder.

This is because the mass, specific gravity, slipperiness, adhesion, and chargeability of powder vary, and even if the hollow pipe is the same, the transportability of powder strongly depends on the characteristics of the powder itself.

The same thing can be said even if the material, surface properties, and chargeability of the hollow pipe change.

However, even if multiple piezoelectric elements are connected to a long hollow pipe to transport powder over a long distance, the vibrations generated by the piezoelectric elements always generate symmetrical traveling waves around the piezoelectric element, and Powder transport in this direction becomes impossible. FIG. 15(B) shows a schematic diagram of each traveling wave generated by a plurality of piezoelectric elements in the same long hollow pipe. FIG. 15(C) shows a schematic diagram of the vibration of the traveling wave excited in the hollow pipe after combining the respective traveling waves, and the magnitude and directionality of the powder conveying force due to the traveling wave.

As is clear from these figures, the powder conveyance force acts in the direction of each piezoelectric element, making it impossible to convey the powder in one direction, and as shown in Figure 15 (A), a branch-like force is generated near each piezoelectric element. This results in powder remaining.

Therefore, in the present invention, the hollow pipe between the piezoelectric elements is divided as shown in FIG. 1, so that the traveling waves generated by the piezoelectric elements do not interfere with the traveling waves generated by other piezoelectric elements.

Furthermore, in order to minimize the effect of the backward waves that it generates, the hollow pipe near the piezoelectric element that generates the backward waves is cut, and a so-called vibration absorbing member, which absorbs vibrations and does not transmit them, is inserted. . In order to explain the action of this vibration absorbing member, FIG. 10(B) shows a schematic diagram of each traveling wave generated by the piezoelectric element.

As shown in FIG. 10, the traveling wave transmitted through the hollow pipe 2 is attenuated by the vibration absorbing member 5, and the traveling wave is not transmitted to the adjacent hollow pipe 2.

FIG. 10(C) shows the vibration of the traveling wave excited in the hollow pipe 2 after combining the respective traveling waves. In addition,
In this example, the application time and application timing to each power source are all the same.

According to this embodiment, by cutting the hollow pipe 2 in which reverse traveling waves occur and inserting a vibration absorbing member between them, the influence of the backward traveling waves can be suppressed to a small level, as shown in FIG. 10(C). It is possible to have a specific magnitude and directionality of the powder conveying force.

As is clear from this, the effective powder conveying force acts in a fixed direction, and the powder is strongly conveyed in the direction of arrow A as shown in FIG. 10(A). That is, by shifting the position of the vibration absorbing member from the point between φ between adjacent piezoelectric elements, powder can be conveyed in the opposite direction to the direction of displacement, and the closer it is to the piezoelectric elements, the greater the conveying force becomes.

By the way, if the vibration width at the end of the hollow pipe 2 in contact with the vibration absorbing member 5 is not attenuated to less than h of the vibration width at the piezoelectric element part, the influence of the reflected wave at the end will be large, and the traveling wave will be This is not preferable because the conveying force will be attenuated greatly. As a result of the experiment, the material used for the powder conveying member has a relatively high attenuation rate, and if the amplitude of the generated excitation is less than the amplitude at the end, it is likely that the influence of reflected waves is small and the conveying capacity is low. I found it to be excellent. According to experiments, acrylic, nylon POM (polyacetal), ABS polypropylene, polystyrene, etc. are suitable. In this embodiment, vibration isolating rubber (NBR) is used as the vibration absorbing member, and the vibration isolating rubber is connected to a hollow pipe using a silicon adhesive.

In addition, vibration absorbing members include NBR, urethane rubber, and Si.
Rubber EKDM, gel-like resin, Si rubber adhesive, etc. are optimal, and by reducing the hardness of the rubber, it is possible to absorb almost 100% of the traveling wave vibration. Furthermore, it has been found through experiments that when the vibration absorption rate is 50%, if the amplitude of the traveling wave propagating through the vibration absorbing member is attenuated below the amplitude, the powder can be conveyed.

In this example, an acrylic hollow pipe is used, and this structure is such that the amplitude of vibrations applied to a part of the acrylic hollow pipe, which is a powder conveying member, is attenuated by the vibration absorption of that member, that is, the acrylic hollow pipe itself. ing. The present invention is configured such that the amplitude of the excited powder conveying member is attenuated at the end in the conveying direction, generating a traveling wave and conveying the powder. It is effective and can be realized easily and inexpensively.

In addition to using materials with high attenuation, the structure can also be made using materials with low attenuation, such as attaching a material with high attenuation to a part of the metal pipe, or adding grooves to the shape of the metal pipe itself to increase the attenuation. There are several examples.

As described above, it has been found that when the application time and application timing to each power source are made the same, good conveyance performance cannot be obtained unless an appropriate vibration absorbing member is selected. So, next,
In order to further ensure reliable conveyance, as shown in FIG. 11, the application time and application timing of the power applied to each piezoelectric element were made so that adjacent piezoelectric elements did not influence each other.

As a result, it was found that good conveyance performance could be obtained even when the vibration absorption rate of the vibration absorption member was 50% or less. This example will be explained below.

In this example, the peak voltage is 100V, and the frequency is 50V.
0N10FF was repeated at 1 second intervals at KHz. As a result, the powder could be transported smoothly over a long distance of 2 meters without clogging. One-component magnetic toner having an average particle size of 12 mm was used as powder, and the conveying force of this powder was 500 g/inch. In addition, there was almost no difference in the conveying force when the application time was up to several seconds apart, but when the application time interval became 10 seconds or more, powder that could be moved to the conveying member or hollow pipe with adjacent piezoelectric elements that were in a stopped state This results in the amount being saturated and the amount of conveyance decreasing.

Furthermore, the powder was mixed with glass beads having an average particle size of 60 mm and ferrite carrier having an average particle size of 60 mm. It has been found that even when using a layer, a non-magnetic toner powder with an average particle size of 8 cm, and a mixture thereof, a conveying force similar to that of the magnetic toner can be obtained depending on the application time.

Furthermore, by using this sequence, each piezoelectric element approaches an independent event, so even if the vibration width at the end of the hollow pipe in contact with the vibration absorbing member or the vibration width at the piezoelectric element part is not attenuated to H or less, the conveyance It turns out that it can hold a certain amount of power.

In this way, since there is no conveying member such as a screw inside the hollow pipe, it has become possible to efficiently convey the powder without degrading, destroying, melting, etc.

In this embodiment, the voltage applied to adjacent piezoelectric elements is 0N1.
The 0FF timing is set so that they do not interfere with each other, or even if there is a certain amount of misalignment, a sufficient conveying force can be ensured.

<Second Embodiment> Next, a second embodiment of the present invention will be described using FIG. 12. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted. .

In the first embodiment, ON/OFF of the voltage applied to the piezoelectric element
By changing the F application time, we prevented the influence of adjacent piezoelectric elements, but by increasing the voltage applied to each piezoelectric element in sequence according to the transport direction, as shown in Figure 12, we could further prevent the traveling waves from interfering with each other. However, it is also possible to increase the transport force by exciting the traveling wave gradually in the transport direction.

(Third Embodiment) Next, FIGS. 13 and 14 show a third embodiment of the present invention.
This will be explained using figures. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

In this example, even if the size and shape of the powder members connected via the vibration absorbing member change, the timing and size of the voltage applied to the piezoelectric elements can be changed to suit the powder conveying member. This is to obtain powder conveying power.

FIG. 13 is a schematic diagram of the third embodiment, and is an example in which the shape of the powder conveying hollow pipe is different. 2-1 is a hollow round pipe with a large diameter, 2-2 is a hollow round pipe with a small diameter, 2-
3. It is a hollow square pipe. Since the shape of each end face is different, in order to match the powder transportability at the connection part, prevent powder clogging, and avoid the influence of traveling waves on adjacent pipes, each end is The magnitude of the voltage applied to the piezoelectric element was changed, and the timing was also shifted. As a result, smooth powder transportation has become possible.

[Effects of the Invention] As explained above, according to the present invention, a traveling wave is generated by applying vibration in the radial direction to the powder conveying member connected by the vibration absorbing member by the vibration generating means. Powder can be transported over long distances efficiently with less energy. In addition, the powder can be transported quietly and smoothly without deterioration, damage, or melting. Furthermore, by changing the magnitude and application time or application timing of the voltage applied to each vibration generating means, it is possible to reliably improve conveyance performance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing a schematic configuration of a vibration generating means of the device shown in FIG. 1, and FIG. Fig. 4 is a perspective view showing a schematic configuration when the means shown in Fig. 2 are laminated, and Fig. 5 is a diagram showing changes in the outer wall of the body conveying member. Fig. 5 shows electrodes provided on the circumference of the means shown in Fig. 2. FIG. 6 is a diagram showing the ((1,1)) mode electrode arrangement of the means in FIG. 2, and FIG. 7 is a diagram showing the powder conveyance in the case of the arrangement shown in FIG. 6. A diagram showing changes in the outer wall of the member, FIG. 8 is a diagram showing changes in the outer wall of the member (
(2,1)) mode, Figure 9 shows the electrode arrangement of the 8th mode.
Figure 10 (A) is a diagram showing changes in the outer wall of the powder conveying member in the case of the arrangement shown in the figure, Figure 10 (A) is a diagram showing the state of powder inside the powder conveying member of the apparatus shown in Figure 1, Figure 10 (B) is 1 is a diagram illustrating the traveling waves generated in the powder conveying member in the apparatus, FIG. 10(C) is a diagram illustrating the traveling waves after combining the traveling waves in FIG. 10(B), 11 is a timing chart showing the timing of voltage applied to each vibration generating means in the apparatus shown in FIG. 1; FIG. 12 is a timing chart showing the timing of voltage applied to each vibration generating means in the second embodiment of the apparatus of the present invention; FIG. 13 is a diagram showing a schematic configuration of a device according to a third embodiment of the present invention, FIG. 14 is a timing chart showing the magnitude and timing of voltage applied to each vibration generating means of the device in FIG. 13, and FIG. ) is a diagram showing the state of powder inside the powder conveying member when no vibration absorbing member is attached to the apparatus in Figure 1, and Figure 15 (B) is a diagram showing the state of powder inside the powder conveying member in the apparatus shown in Figure 15. FIG. 15(C) is a diagram illustrating a traveling wave after combining the traveling waves in FIG. 15(B).

Claims (7)

[Claims] (1) A tubular or trough-like powder conveying member that conveys powder in the longitudinal direction, vibration generating means arranged at multiple positions in the longitudinal direction of the member, and the magnitude of the driving voltage applied to each of the vibration generating means. 1. A powder conveying device comprising: control means for controlling application time or application timing differently. (2) The powder conveying device according to claim (1), wherein the powder conveying members between the plurality of vibration generating means are connected via a vibration absorbing member. (3) A claim in which the powder conveying member is configured such that the amplitude of the powder conveying member excited by the vibration generating means is attenuated and becomes smaller at an end in the traveling direction of the traveling wave of the powder conveying member. The powder conveying device according to claim (1) or claim (2). (4) A claim in which a vibration absorbing member is used in which the amplitude of the traveling wave propagating through the powder conveying member is zero or small (
1) or the powder conveying device according to claim (2). (5) The powder conveying device according to claim (1) or claim (2), wherein the vibration generating means uses a piezoelectric element. (6) The powder conveying device according to claim (1) or (2), wherein the powder conveying member is a hollow pipe. (7) The powder conveying device according to claim (1) or claim (2), wherein the vibration absorbing member is a resin or rubber adhesive.