JP4002162B2 - Powder coating apparatus and in-mold lubricating compacting apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a powder coating apparatus and an in-mold lubricating compacting apparatus for powder metallurgy equipped with the apparatus, and in particular, devised so that a predetermined amount of powder can be stably and efficiently supplied and coated. The present invention relates to a coating apparatus and a compacting apparatus in which the apparatus is applied to the application of an in-mold lubricant for powder metallurgy.
[0002]
The present invention is particularly effective as an intermittent application device for applying a powdery in-mold lubricant to the inner surface of a mold when a metal powder for powder metallurgy is compacted by adopting an in-mold lubrication method. Since it can be utilized, the following description will focus on intermittent application of such a powdery in-mold lubricant. However, the present invention is not limited to such a use as a matter of course, and can be effectively applied to all uses where it is required to supply and apply a predetermined amount of powder with high accuracy.
[0003]
[Prior art]
When compacting metal powder for powder metallurgy with a metal mold, in order to perform compaction smoothly, usually an appropriate amount of lubricant is mixed in the metal powder, and the metal powder and metal powder and mold are mixed. A method for increasing the lubricity between the inner surfaces is employed. However, the portion where lubrication is most necessary is a contact portion between the metal powder and the inner surface of the mold, and the role played by the internal lubricant is relatively small.
[0004]
On the other hand, the lubricant mixed in the metal powder becomes an impurity and causes the density and strength of the green compact to be lowered, and further, it takes time for dewaxing during sintering, so it can be suppressed to a small amount. desired. For these reasons, recently, the in-mold lubrication method has been widely used in which the amount of internal lubricant blended in the metal powder is reduced as much as possible, and the in-mold lubricant is applied to the inner surface of the mold and compacted. Yes.
[0005]
In addition, as a method of applying the in-mold lubricant to the inner surface of the mold, in the case of a liquid lubricant or a slurry lubricant, brush coating or spray coating is adopted, such as a salt or ester of a higher fatty acid such as stearic acid. When a solid lubricant is used at room temperature, a method is commonly used in which the lubricant is powdered and uniformly adhered to the inner surface of the mold by an electrostatic adhesion method.
[0006]
When applying the in-mold lubricant by the electrostatic adhesion method, for example, the powdered lubricant is applied to the inner surface of the mold in accordance with the compacting cycle that is repeated in a very short cycle of 3 to 30 times / min. It is difficult to carry out the process with high accuracy, and the adhesion amount of the lubricant may fluctuate and cause molding defects. Therefore, it is necessary to establish a technique capable of reliably supplying a necessary and sufficient amount of lubricant in accordance with the compacting cycle so that the lubricant can be uniformly applied to the inner surface of the mold.
[0007]
Under such circumstances, for example, Patent Document 1 proposes an in-mold lubricant application device using a powder circulation channel. This apparatus employs a system in which a powdery lubricant is continuously circulated in a circulation flow path and the flow path is switched for a predetermined time during spraying of the lubricant to be sprayed to a site to be coated.
[0008]
However, since this method is not basically a method for performing quantitative cutout, it is not only difficult to confirm the spray supply amount for each time, but also the spray supply amount cannot always be maintained constant. That is, in this method, since the powder is constantly circulated together with the airflow (carrier gas), a part of the powder adheres to the tube wall surface of the circulation line during the circulation process, or the adhered and deposited powder falls off at a certain time. In some cases, the powder concentration in the circulation channel varies considerably. In addition, the powder may block due to static electricity generated by contact between powders and friction with the inner surface of the pipe during circulation, and these together cause considerable fluctuations in the concentration and particle size of the powder circulating in the flow path. Therefore, the supply amount of the powder lubricant supplied to the mold application surface varies considerably. Therefore, in the intermittent supply process, the in-mold lubricant may be insufficiently supplied or excessively supplied, which adversely affects the stable operation of the compacting itself.
[0009]
On the other hand, in the field of powder coating, various proposals have been made for improved equipment that can feed a predetermined amount of powder coating stably and continuously by feeding it to the spray nozzle part by air flow transportation while cutting out the powder coating. Has been. For example, Patent Document 2 discloses a screw-type quantitative cutting device for powder coating. And it is devised so that fixed amount cutting can be performed by directly connecting the screw of the cutting portion to a reduction motor and rotating the screw for the driving time of the motor.
[0010]
However, since the powder coating apparatus is generally premised on continuous coating of several minutes to several tens of minutes, it is difficult to apply to a powder molding apparatus for powder metallurgy that is repeatedly performed at an intermittent application cycle of about 0.1 seconds. In particular, in the above powder coating apparatus, the amount of powder supplied after reaching the steady spray supply state is kept substantially constant, but the amount of powder supplied at the start-up of the drive motor, which is the drive source of the quantitative cutting screw, is insignificant. Since stable and considerable fluctuations are unavoidable, and the rise time alone takes time in seconds, it is applied to intermittent supply of the powder metallurgy in-mold lubricant that is repeated in a short cycle such as 0.1 second to several seconds. It is virtually impossible.
[0011]
Further, Patent Document 3 discloses a method of preventing spraying of supplied powder by performing a control operation using a plurality of electromagnetic valves when performing quantitative cutting using a screw-type supply device. Yes. However, this method also basically performs intermittent supply of powder by switching a plurality of electromagnetic valves while circulating the powder, and the problems derived from the circulation are retained as it is, and for example, a few seconds or less. It cannot cope with stable quantitative intermittent supply in a short cycle.
[0012]
Furthermore, in any of these methods, a mechanism for automatically detecting whether or not a predetermined amount of powder has been reliably delivered in the direction of the spray nozzle, a mechanism for automatically informing the abnormality when a feeding amount abnormality occurs, Does not come with an automatic control mechanism that correlates the abnormal feeding amount to the stoppage of driving of related equipment.For example, an appropriate amount of powder lubricant for in-mold lubrication due to some trouble in powder metallurgy compacting When the situation where it is not supplied occurs, seizure occurs in the compacting mold, which deteriorates the quality of the compacted article and leads to damage to the mold and the press device.
[0013]
[Patent Document 1]
JP 2001-220602 A
[Patent Document 2]
JP-A-8-290096
[Patent Document 3]
JP 2001-29848 A
[0014]
[Problems to be solved by the invention]
The present invention has been made paying attention to the circumstances as described above, and its purpose is to intermittently apply powder such as in-mold lubricant into the mold when performing in-mold lubrication molding for powder metallurgy, for example. Even in such a case, it is possible to stably and reliably supply a predetermined amount of powder, and if an abnormality occurs in the feeding amount, the abnormality is immediately notified, or further, the feeding amount By providing an automatic control mechanism that automatically detects abnormalities and automatically stops the driving of related equipment, a coating apparatus capable of preventing a situation where the system is continuously operated in an abnormal state is provided. Is to provide a compacting device that effectively utilizes the features provided in the in-mold lubrication for powder metallurgy.
[0015]
[Means for Solving the Problems]
The present invention that has been able to solve the above problems is a powder supply unit, a quantitative cutting device connected to the powder supply unit and operated intermittently, and a transport for air-transporting the powder intermittently cut from the quantitative cutting device A pipe, a nozzle for spraying the powder to the application part, a charging part for frictionally charging the powder provided in the airflow transport pipe and / or the spray supply nozzle, and a charge amount of the frictionally charged powder And a charge amount signal detected discontinuously by intermittent operation of the quantitative cutting device is converted into a voltage that can be detected at all times, and the converted charged voltage is set in a preset band. A charging signal processing unit that determines whether or not the voltage is within a voltage range and detects an abnormality in the voltage and activates an alarm device and / or stops the quantitative cutting device. The Ete made it to the gist.
[0016]
In the present invention, the powder can be applied as an in-mold lubricant to the inner surface of the mold when the powder for powder metallurgy is compacted.
[0017]
In the present invention, the quantitative cutting device is an intermittent drive type, and if the powder can be intermittently supplied to the coated portion, quantitative intermittent supply of the powder can be efficiently performed in a short cycle, Therefore, such an apparatus can be effectively used for intermittent application of the in-mold lubricant to the inner surface of the mold when the powder for powder metallurgy is compacted.
[0018]
In addition, the charging unit is configured to be provided in the airflow transportation pipeline to charge the powder by frictional charging, and the charge amount of the powder lubricant charged by the charging unit can be detected by a detection device. When a charging signal processing unit is connected to the detection device and the charged voltage detected by the detection device is outside the preset charging voltage range input in advance to the charging signal processing unit, an abnormality in the charging voltage is detected. If a mechanism for operating the alarm device is provided, the operator can immediately know the abnormal powder feed.
[0019]
In addition, the charging signal processing unit has a function of outputting a stop signal for stopping the powder quantitative cutting device at the same time as detecting an abnormality in the charged voltage, or a stop signal for further stopping the compacting mold device. If this is the case, problems caused by an abnormality in the powder feed amount, for example, compacting molding failure and seizure accidents due to insufficient mold lubrication can be prevented in advance.
[0020]
Further, in the present invention, the apparatus described in claim 2 is connected to a compacting mold apparatus, and the quantitative cutting apparatus is intermittently driven in accordance with the compacting cycle of the mold apparatus, and spraying is performed. If the control part which intermittently supplies a powder lubricant to a metal mold | die inner surface from a supply nozzle is provided, it will become the in-mold lubrication compacting apparatus which is another embodiment of this invention.
[0021]
Further, in the in-mold lubricating powder molding apparatus, when the charged voltage detected and converted by the detecting device is out of a preset charged voltage range, the charged signal processing unit May be configured to output a stop signal for stopping the operation of the compacting device.
[0022]
As described above, when the charged voltage detected and converted by the detecting device is out of the preset charged voltage range, the abnormality of the charged voltage is detected and the operation of the mold apparatus for compacting is performed. If the operation is stopped, it is possible to prevent a compacting molding abnormality resulting from a poor supply of the in-mold lubricant.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, the present invention provides a charging unit that frictionally charges the powder to the airflow transport line and / or the spray supply nozzle when the powder is quantitatively cut out and transported by airflow and fed from the spray supply nozzle to the application portion. The feeding amount is always detected by detecting the charged voltage applied to the powder at the charging unit, and when an abnormality occurs in the feeding amount, the abnormality is detected and the alarm device is activated. And / or has a basic feature where a charge signal processing unit for stopping the quantitative cutting device is provided, and the type of powder to be supplied is not particularly limited, but the feature of the present invention is most effectively utilized. This is the case where intermittent supply of in-mold lubricant to the mold is automatically performed when compacting for powder metallurgy using the in-mold lubrication method. Drawings showing typical examples, mainly using the internal lubrication compacting method While irradiation will be described the present invention more specifically.
[0024]
However, the present invention is not limited to the following illustrated examples, and can be implemented with appropriate modifications within a range that can be adapted to the purpose described above and below. To be included in the scope.
[0025]
FIG. 1 is a schematic explanatory view showing an embodiment of the present invention, and exemplifies an apparatus that performs in-mold lubrication compacting by adopting a quantitative cut-out feeder using a screw mechanism and an air conveyance / spraying mechanism. .
[0026]
In the figure, 1 is a powder lubricant supply hopper, 2 is a stirring blade, 3 is a stirring motor, 4 is a vibration exciter, 5 is a screw for quantitative cutting, 6 is a drive motor, 7 is an electromagnetic clutch, and 8 is a quantitative supply hopper. , 9 is a powder air flow feeding device, 10 is a charging unit, 11 is an alarm device, 12 is a compacting mold device having a spray nozzle, etc., and 13 is an automatic detection / control unit (control unit). Yes.
[0027]
In this apparatus, a fixed quantity cutting screw 5 is connected to a lower part of a powder lubricant supply hopper 1 provided with a stirring blade 2 driven by a stirring motor 3 and a vibrator 4. The screw 5 is connected to a drive motor 6 via an electromagnetic clutch 7 and operates a compacting mold apparatus 12 as described later (opening of the mold → application of lubricant in the mold → supply of raw material powder). → Compact molding → Opening of mold → Removal of compacted compact) In accordance with the cycle, the powder clutch is intermittently driven by the electromagnetic clutch 7 in order to supply the powder lubricant in the mold direction.
[0028]
That is, the screw 5 connected to the lower portion of the powder lubricant supply hopper 1 is intermittently driven according to the switching cycle of the electromagnetic clutch 7 and intermittently feeds a predetermined amount of powder lubricant toward the supply hopper 8. In the figure, 14 is a flowing air device, and the powder lubricant flowing down from the powder lubricant supply hopper 1 is clogged or suspended in the lower part of the hopper 1 or in communication with the screw 5 so that quantitative cutting is not possible. In order to prevent it from becoming stable, air for flow is supplied from below the communicating portion, and the function of stabilizing the quantitative cutout of the powder lubricant according to the rotation of the screw 5 is achieved.
[0029]
The powder lubricant that has been cut out from the tip of the screw 5 into the fixed amount supply hopper 8 by a predetermined amount is sucked in the direction of the transport line L by a carrier gas (usually air) by a powder airflow feeding device 9 by, for example, a venturi mechanism. The whole amount is discharged and conveyed toward the downstream compaction mold apparatus 12.
[0030]
A charging unit 10 is provided on the upstream side of the compaction mold device 12 in the transport pipeline L, and the powder lubricant transported in the pipeline L is charged in the process of passing through the charging unit 10. Then, it is sent in the direction of the compacting mold device 12. For example, as shown in FIG. 2, the charging unit 10 has an inner wall made of a highly chargeable material such as polyfluoroethylene, and when the powder lubricant passes through the charging unit 10, The powder lubricant is charged by friction between the peripheral surface and the powder. In this device, in order to keep the amount of charge applied to the powder lubricant as constant as possible, only the inner peripheral wall of the charging unit 10 is made of a highly chargeable material, and the transport line L other than the charging unit 10 causes frictional charging as much as possible. Consists of difficult materials.
[0031]
Therefore, in this charging unit 10, as long as the amount and flow rate of the powder lubricant transported in the pipe L are constant, the powder lubricant is given a constant charged voltage, and the charge amount is Always detected as a charging signal. If an abnormality occurs in the powder lubricant quantitative cut-out line, the charged voltage fluctuates due to fluctuations in the amount of powder lubricant passing through the charging unit 10, but the fluctuations are immediately sent to the automatic detection / control unit 13. This signal is immediately sent to the alarm device 11 or a stop signal is output to the quantitative cutting screw 5 and the molding die device 12, which will be described later.
[0032]
The charging unit 10 for triboelectrically charging the powder may be any powder feeding path from the fixed amount cutting part of the powder lubricant to the molding die device 12, and depending on the case, the powder may be supplied to the molding die device 12. Although it is possible to provide the nozzle portion for supplying the spray, it is usually desirable to provide it slightly upstream of the nozzle.
[0033]
In the example of FIG. 1, the powder lubricant charged by the charging unit 10 is then blown into the mold from a powder supply nozzle arranged facing the compacting mold apparatus 12 and electrostatically applied to the inner surface of the cavity. Is done.
[0034]
3 to 7 are schematic cross-sectional explanatory views illustrating the specific structure and operation mechanism of the compacting mold apparatus 12, and are a fixed type die D and a vertically movable punch P. ₁ , P ₂ Is the main component, the inner peripheral wall of the die D and the punch P ₁ , P ₂ Fill the cavity surrounded by the upper and lower surfaces with metal powder for compacting and punch P ₁ , P ₂ By pressing from above and below, compacting is performed.
[0035]
In the figure, A is a metal powder supply device, N is a powder lubricant supply nozzle attached to the tip position thereof, and a punch P is used for compacting. ₂ Is lowered to a predetermined position to ensure a predetermined cavity capacity, and then a powder lubricant is first supplied from the powder lubricant supply nozzle N into the cavity, and the static electricity provided by the charging unit 10 is used. A powder lubricant is electrostatically attached to the inner wall surface of the cavity. At this point, metal powder Me, which is a raw material for compacting, is loaded in the metal powder supply apparatus A (FIG. 3).
[0036]
Next, the supply of the powder lubricant from the nozzle N is stopped, and the rod R is operated to advance the metal powder supply device A to supply a predetermined amount of metal powder into the cavity (FIG. 4). Thereafter, when the rod R is operated to retract the metal powder supply device A and the nozzle N from the cavity position, a predetermined amount of metal powder is filled in the mold cavity. Subsequently, as shown in FIG. ₁ And lower punch P if necessary ₂ Is also raised simultaneously to perform compacting (FIG. 6).
[0037]
After compacting is complete, punch P ₁ And die D (and / or punch P) ₂ After the green compact S is exposed from the cavity, the compact S is discharged out of the mold apparatus 12 by a pusher (not shown) (FIG. 7).
[0038]
Then, after the discharge of the green compact S is completed, the process returns to the step shown in FIG. 3 again, the rod R is operated to advance the powder lubricant supply nozzle N to the cavity position of the mold, and then the nozzle A powder lubricant is sprayed from N and applied to the inner surface of the cavity.
[0039]
Application of powder lubricant to cavity inner surface → Quantitative supply of metal powder → Punch P ₁ , P ₂ By forming a series of processes consisting of compacting by pressing → taking out compacted compact S as one cycle, compacting is repeated intermittently at a short cycle of, for example, 3 to 30 times / min. The green compacting is performed.
[0040]
In order to smoothly perform such intermittent compaction molding, a predetermined amount of powder lubricant is stably supplied into the cavity in accordance with the above-described intermittent operation cycle of the mold apparatus 12 and intermittently applied. However, at this time, the intermittent supply device of the powder lubricant as illustrated in FIG. 1 exhibits its function. When an abnormality occurs in the supply of the powder lubricant, the abnormality is immediately detected by the automatic detection / control unit 13, the alarm device is activated to notify the operator, and / or the quantitative cutting device is stopped. Or, further, by stopping the operation of the mold apparatus for compaction molding, it is possible to prevent the operation with the feeding abnormality from continuing. Hereinafter, the intermittent supply mechanism of the powder lubricant will be described again with reference to the illustrated example of FIG.
[0041]
This equipment is configured so that it can be centrally managed by the automatic detection / control unit 13, and the automatic detection / control unit 13 includes the agitation motor 3, the vibration exciter 4, and the drive motor 6 for the quantitative cutting screw 5. , An electromagnetic clutch 7, a powder airflow feeding device 9, a fluidized air supply unit 14, and other driving sources are electrically connected, a voltage detection unit of the charging unit 10, an alarm device 11, and the above-described powder molding metal The punch P in the mold apparatus 12 ₁ , P ₂ Further, the metal powder supply device A, the forward / backward operation source of the rod R for moving the powder supply nozzle N back and forth, and the like are electrically connected, and the above-described series of steps can be automatically controlled and operated.
[0042]
More specifically, the automatic detection / control unit 13 includes, for example, timers 1 to 4 and the air adjusters 1 and 2 and the like. ₁ , P ₂ The timing of supplying the powder lubricant including the intermittent drive of the electromagnetic clutch 7 is set in accordance with the intermittent operation cycle such as the vertical movement or advance / retreat of the rod R and the opening / closing of the powder lubricant supply nozzle N. In addition, in the timers 2 to 4, the preliminary injection time is used in the timer 2, the cutting time is used in the timer 3, and the cutting time is used in the timer 4 so that the entire amount of the powder lubricant that is quantitatively cut out from the screw 5 can be reliably delivered downstream. In addition to adjusting the post-injection time, the air regulator 1 adjusts the transfer air pressure, and the air adjuster 2 adjusts the flow air pressure.
[0043]
And these are punch P in the said compacting die apparatus 12 ₁ , P ₂ Further, the powder lubricant is intermittently fed to the mold cavity by being operated in accordance with an intermittent operation cycle such as a forward / backward operation source of the rod R for advancing and retreating the powder supply nozzle A and the powder supply nozzle N.
[0044]
For example, FIG. 8 is an explanatory diagram showing an example of the timer operation in the powder lubricant quantitative cut-out section. The drive motor 6 is continuously driven, and the electromagnetic clutch 7 is intermittently operated in accordance with the intermittent supply timing of the powder lubricant. By doing so, the powder lubricant is quantitatively cut out from the screw 5. At this time, the conveying air and the auxiliary air are supplied for a long time before and after the operation time of the electromagnetic clutch 7 so that all of the powdered lubricant that is quantitatively cut out can be reliably fed downstream. The stirring motor 3 and the vibration exciter 4 are operated slightly extended after the electromagnetic clutch 7 is stopped so that the powder lubricant to be cut out in the next step is surely sent to the quantitative cutting screw 5.
[0045]
Such intermittent drive time is automatically controlled by the timer mechanism described above. The set time of the timer can be arbitrarily adjusted according to the size and shape of the green compact, the target productivity, etc., and should not be interpreted restrictively, but as a general guideline, for example, T ₁ Is 0.1 to 10 seconds, T ₂ Is 0.1 to 3 seconds, T _Three 0.1 to 5 seconds (accuracy can be guaranteed in units of 0.01 seconds), T _Four Can be considered as about 0.1 to 3 seconds.
[0046]
In other words, in this example, a fixed quantity cutting device is connected to a drive motor via an electromagnetic clutch and driven intermittently, and stable feeding using carrier air is realized, so that it is difficult to intermittently apply short cycles in the conventional example. It becomes possible to efficiently carry out intermittent compacting that employs the in-mold lubrication in a short cycle.
[0047]
In the illustrated example, an example using the most versatile screw mechanism as the quantitative cutting device is shown. However, the present invention is not limited to this, and it is of course possible to adopt a quantitative cutting mechanism such as a table feeder or a bucket feeder. Is possible. Further, the specific structure of the powder supply hopper 1 can be arbitrarily changed in accordance with the cutting mechanism of the quantitative cutting device, and the specific configuration of the airflow feeding device 9 is basically the amount of the powder to be quantitatively cut out. A specific structure is not limited as long as it has a function capable of reliably carrying the entire air flow.
[0048]
By the way, if the powder lubricant is supplied in a fixed quantity, in-mold lubrication, and compaction molding are actually performed using the apparatus shown in the drawing, the fluctuation of the cutting amount is suppressed as much as possible by intermittent quantitative cutting using an electromagnetic clutch. However, depending on fluctuations in the flow characteristics of the powder lubricant due to changes in atmospheric humidity, etc., or fluctuations in the quantitative cutout part including slight fluctuations in the pressure of the supply air, the amount of powder lubricant delivered may vary. It can change slightly. In particular, when the supply amount of the powder lubricant is insufficient, the inner surface of the compacting mold becomes insufficiently lubricated, causing seizure on the inner surface of the mold or insufficient compaction. Or cause damage to the mold.
[0049]
Therefore, in the present invention, assuming such a situation, the feed amount of the powder lubricant to be fed is always detected, and when the feed amount fluctuates beyond the allowable range, it is immediately detected, and immediately by the alarm device. An automatic stop mechanism is provided for notifying the operator and / or stopping the quantitative cutting device, or further stopping the operation of the compacting mold device.
[0050]
FIG. 2 described above shows that when an abnormal feeding of the powder lubricant as described above, in particular, an insufficient feeding occurs, the abnormality is automatically detected and an alarm mechanism is activated to notify the operator. Alternatively, the mechanism that can stop the quantitative cutting device, or automatically stop the operation of the compacting mold device by the detection signal, and prevent the occurrence of defective molding or damage to the die device. It has.
[0051]
That is, as described above with reference to FIG. 2, the charging unit 10 shown in the figure has an inner peripheral surface made of a highly chargeable material such as polyfluoroethylene, and the powder passing through the inside with gas entrained is the inner peripheral surface. It has the function of charging by friction. This charging mechanism has the advantage that the powder lubricant can be easily and quickly charged without significantly increasing the flow path resistance, and the charging amount of the powder lubricant passing through the charging unit 10 is taken as a charged voltage. It has the advantage that it can be easily detected from the outside. As a result of confirmation by the present inventors, when such triboelectric charging is adopted, if a charging signal taken out from the charging unit 10 is converted into a charged voltage, the powder lubricant conveyed while being charged is fed. The supply amount can be detected quantitatively.
[0052]
In the present invention, utilizing such knowledge, a friction charging portion is provided in the powder transportation pipeline or spray supply nozzle, and the amount of charge at the time of feeding the powder lubricant is converted into a charged voltage by the friction charging portion. Quantitatively detect the amount of feed. When the amount of powder lubricant is changed, the change is immediately detected and immediately notified to the operator. Especially when the amount of supply is insufficient, the powder lubricant metering device is stopped. In addition, by automatically stopping the compacting mold device, abnormal operation of the mold device (for example, seizure of the mold or lack of compaction, etc.) due to an abnormal supply amount of the powder lubricant can be prevented in advance. I am doing so.
[0053]
Specifically, as shown in FIG. 2, a charging signal processing unit 15 is provided in addition to the charging unit 10, and the powder is conveyed to the arithmetic processing unit provided in the processing unit 15 in a steady state. In advance, a charged voltage corresponding to the amount of charge generated is input as a standard voltage. When intermittently supplying the powder lubricant, the actual charge amount generated when the powder lubricant is charged and fed is converted so that it can be detected at any time by converting the voltage if necessary. To determine the amount of powder lubricant to be conveyed. When the charged voltage of the powder lubricant during actual conveyance falls below the preset standard voltage allowable range, the signal is transmitted to the alarm device to display (notify) the abnormality and quantitative cutout. A stop signal is issued to the drive source of the part, or further, it is transmitted to the intermittent drive source of the compacting mold device 12 to instruct to stop driving the mold device 12. The charging signal processing unit 15 can be provided separately from the charging unit 10 as shown in the figure, but is usually automatically incorporated into the automatic detection / control unit 13 as shown in FIG. Be controlled.
[0054]
FIG. 9 is a diagram exemplifying the fluctuation pattern of the charged voltage at this time. The charged voltage detected by the charging unit at the time of normal intermittent supply is, for example, approximately 8 V, and this charged voltage is maintained. As long as it is done, the intermittent powder feed amount (feed amount per cycle) is kept constant. However, when the amount of powder passing through the charging portion decreases due to an abnormality in the quantitative cutout portion, the state immediately appears as a decrease in the charged voltage. Accordingly, the lower limit value of the normal charged voltage is input in advance to the charging signal processing unit 15, and when the detected charged voltage falls below the set value, the signal is transmitted to the alarm mechanism 11 or quantified. A control line may be set so that the drive source of the cutting device is stopped and further output as a drive stop signal of the compacting mold device 12.
[0055]
If such an automatic detection / control mechanism is attached, when a feed amount abnormality exceeding an allowable error occurs in the powder lubricant that is conveyed from the quantitative cutout portion and fed into the mold apparatus 12, the operator The abnormality can be confirmed immediately, and by operating the automatic stop mechanism for the quantitative cutout part and the mold molding device, the occurrence of defective molded products, damage to the mold device due to die seizure, etc. This can be prevented beforehand.
[0056]
By the way, in the example of FIG. 1 described above, an example of adopting a mechanism that intermittently transmits the power of the drive motor 6 to the quantitative cutting screw 5 via the electromagnetic clutch 7 is suitable for intermittent supply in an extremely short cycle. However, as described above, the essential feature of the present invention is that the supply pipe (and / or the spray supply for supplying the powder to the application part by spraying the powder cut from the quantitative cutting device by air flow) Nozzle) is provided with a charging unit that frictionally charges the powder, and the charging unit detects the charged voltage applied to the powder, and the signal is detected by the automatic detection / control unit. When the set voltage range that is input in advance to the detection / control unit is out of range, an automatic operation is performed to detect an abnormality in the charged voltage and to activate the alarm device, and to stop the driving source of the quantitative cutting device and mold device. Detection / control machine Since it is characterized in the place incorporated, as long as having such automatic detection and control mechanisms, can be similarly applied to various powder coating apparatus other than that shown.
[0057]
For example, the electromagnetic clutch in the illustrated example is omitted, a mechanism in which powder is cut out intermittently by directly connecting a fixed amount cutting screw to a drive motor and intermittently driving the motor, or the above-mentioned JP 2001-220602 A is disclosed. As described in the above, a mechanism that uses an air pump as a cutting device, performs quantitative intermittent supply by adjusting the pressure of the supply gas and purge gas, and further, controls the rotational speed of a rotary valve that cuts out a fixed volume and cuts out. It is also possible to implement by incorporating the automatic detection / control mechanism of the present invention in a method of transporting by transporting air.
[0058]
Furthermore, the powder intermittent supply apparatus of the present invention is an application that requires quantitative intermittent supply of powder in addition to intermittent supply of powder lubricant when powder metallurgy powder is compacted by in-mold lubrication molding method. , For example, application of lubricant for sizing of sintered parts, application of lubricant in hot forging, application of mold release agent by tablet molding, inner coating of fluorine powder resin etc. on the inner surface of metal containers such as aluminum, motorcycle It can be effectively used in various fields, such as the application of rust preventive powder resin to the inner surface of tire spokes.
[0059]
【The invention's effect】
The present invention is configured as described above, and in particular, a transport conduit for air-transporting the powder cut from the quantitative cutting device, and / or a spray supply nozzle for spraying the powder to the application part, A charging unit that frictionally charges the powder is provided, and the charging voltage applied to the powder is detected by the charging unit, and the signal is detected by an automatic detection / control device, and the charging voltage is preliminarily applied to the detection / control device. Incorporates a control mechanism that can detect the abnormality of the charged voltage and activate the alarm device when it is outside the set charged voltage range, and can automatically stop driving the quantitative cutting device and mold device As a result, it is possible to prevent the occurrence of defective products due to insufficient application, and to increase the product yield. Furthermore, since the overload to the equipment which may be caused by insufficient supply of powder is reduced, it is extremely useful for maintenance of the equipment.
[0060]
Therefore, this coating apparatus can effectively utilize the in-mold lubricant as an intermittent coating apparatus on the inner surface of the mold particularly when the powder for powder metallurgy is compacted.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram showing the overall configuration of an in-mold lubricating powder compacting apparatus using a powder coating apparatus according to the present invention.
FIG. 2 is an explanatory diagram illustrating a configuration of a charging unit and a mechanism for automatically detecting and controlling a powder supply amount using a charged voltage.
FIG. 3 is a schematic explanatory view showing an example of a specific structure and an operation mechanism of a compacting mold apparatus.
FIG. 4 is a schematic explanatory view showing an example of a specific structure and an operating mechanism of a compacting mold apparatus.
FIG. 5 is a schematic explanatory view showing an example of a specific structure and an operation mechanism of a compacting mold apparatus.
FIG. 6 is a schematic explanatory view showing a specific structure and an example of an operation mechanism of a compacting mold apparatus.
FIG. 7 is a schematic explanatory view showing an example of a specific structure and an operating mechanism of a compacting mold apparatus.
FIG. 8 is an explanatory diagram showing an example of a timer operation in a powder lubricant cutting part.
FIG. 9 is a diagram illustrating an example of a fluctuation pattern of a charged voltage detected by a charging unit.
[Explanation of symbols]
1 Powder lubricant supply hopper
2 Stirring blade
3 Stirring motor
4 Exciters
5 Screw for quantitative cutting
6 Drive motor
7 Electromagnetic clutch
8 Fixed supply hopper
9 Powder air flow feeder
10 Charging part
11 Alarm device
12 Compaction mold equipment
13 Automatic detection / control unit
14 Fluid supply section
15 Charging signal processing mechanism
L Supply pipeline
D dice
P ₁ , P ₂ punch
A Metal powder feeder
N Powder lubricant supply nozzle
R rod
Me Metal powder for powder metallurgy

Claims (4)

A powder feeder,
Quantitative cut device that is intermittently operated is connected to the powder supply unit,
And pipelines for gas flow conveyance intermittently cut powder from the constant weight cut device,
A nozzle spray supplying the powder to be coated portion,
A charging unit provided in the air flow transportation line and / or spray supply nozzle for frictionally charging the powder ;
A detection device that detects the charge amount of the frictionally charged powder as a signal ;
The charge amount signal detected discontinuously by the intermittent operation of the quantitative cutting device is converted into a voltage that can be detected at all times, and it is determined whether the converted charged voltage is within a preset set voltage range. when outside the set band voltage range, it detects an abnormality of the band voltages actuates an alarm device, and / or characterized by comprising Bei Ete a quantitative cutout device charging signal processing unit stopping Powder coating device. The coating device according to claim 1 , wherein the powder is applied as an in-mold lubricant to the inner surface of the mold when the powder for powder metallurgy is compacted . Constituted by connecting a device according to claim 2 in powder molding die apparatus, in accordance with the compacting cycle of the mold apparatus, is intermittently drive the quantitative cutout device, gold from the spray supply nozzle An in-mold lubricating powder compacting apparatus comprising a controller for intermittently supplying a powder lubricant to the inner surface of the mold. Actuation of said detected as a charge amount signal I by the detection device, the converted band voltage, when an off-set band voltage range that is set in advance, the charging signal processing unit device for the compacted The in-mold lubricating powder compacting device according to claim 3, which is configured to output a stop signal for stopping the operation .

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