JP4732507B2 - Powder coating device for the inner surface of the injection sleeve - Google Patents

Description

  The present invention relates to a powder coating apparatus for applying powder as a lubricant and a heat insulating agent to an inner surface of an injection sleeve in a casting apparatus such as a die casting machine.

  Conventionally, in this kind of invention, while generating static electricity by the electrode rod inserted from the pouring port into the injection sleeve, the powder is sprayed from the powder injection nozzle (lubricant supply nozzle) toward the pouring port, There is one in which the sprayed powder is electrostatically applied to the inner surface of the injection sleeve. (For example, see Patent Document 1)

  By the way, according to the above prior art, powder adheres to the entire inner surface of the sleeve, but the molten metal flowing in the injection sleeve mainly flows on the lower side in the injection sleeve, and the upper side of the injection sleeve is in contact with the molten metal. Few.

  According to the above prior art, the powder adheres to unnecessary portions, particularly the upper side of the injection sleeve that does not come into contact with the molten metal, so that the amount of the powder scraped by the chip and caught in the molten metal increases. , A lot of powder flows into the cavities with the molten metal. More specifically, if powder adheres to the upper side of the sleeve, the powder is scraped off by the tip and falls into the molten metal flowing under the sleeve, so that the powder and the molten metal enter the cavity. More powder flows in.

Therefore, powder may be mixed in the fracture surface of the sprue of the cast product due to powder contamination, or the powder mixed in the product may cause blistering or casting defects. Quality will deteriorate. In addition, there is a problem that the amount of powder used is large.
Japanese Examined Patent Publication No. 6-69607 (FIG. 5)

  The present invention has been made in view of the above-described conventional circumstances, and the process as the subject is to prevent the powder sprayed from the powder spray pipe from being attached to unnecessary portions in the injection sleeve, In particular, the amount of powder adhering to the upper side of the injection sleeve that does not come into contact with the molten metal is almost eliminated, and by this, there is almost no powder that is scraped off by the chip and caught in the molten metal, and mixed into the product. It is an object of the present invention to provide a powder coating device for the inner surface of an injection sleeve that can reduce the amount of the injection sleeve and, by extension, can stably ensure the quality of a cast product.

In order to achieve such an object, the present invention provides a powder coating apparatus for electrostatically coating powder on the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus, comprising a conductive metal tube, A powder ejection pipe inserted into the injection sleeve, acting as an electrode rod for generating an electrostatic electric field in the injection sleeve, and for injecting the powder into the injection sleeve;
The powder jet pipe is provided with a plurality of powder jet outlets for jetting the powder toward the lower part in the injection sleeve arranged in the substantially horizontal direction, and the powder jet outlet An interference body is provided for preventing the powder ejected from the fluid from flowing upward in the injection sleeve .

Further, the present invention is a powder coating apparatus for electrostatically applying powder to the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus, comprising a conductive metal tube, inserted into the injection sleeve, A powder jet pipe that acts as an electrode rod for generating an electrostatic electric field in the injection sleeve and jets the powder into the injection sleeve, and the powder jet pipe is arranged in the substantially horizontal direction. A plurality of powder outlets for discharging the powder toward the lower part in the injection sleeve are arranged downward in the axial direction, and close to or in contact with the inner peripheral surface of the injection sleeve. A partition body for securing a substantially partitioned space on the side, wherein the powder is ejected from the powder ejection port toward a lower portion in the injection sleeve in the space.

Further, the present invention is a powder coating apparatus for electrostatically applying powder to the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus, comprising a conductive metal tube, inserted into the injection sleeve, A powder jet pipe that acts as an electrode rod for generating an electrostatic electric field in the injection sleeve and jets the powder into the injection sleeve, and the powder jet pipe is arranged in the substantially horizontal direction. A plurality of powder outlets for discharging the powder toward the lower part in the injection sleeve, and a gas outlet for discharging gas toward the upper space in the injection sleeve. A gas ejection pipe is provided.

  According to the powder coating apparatus for the inner surface of the injection sleeve of the present invention, the powder application tube includes a powder jet pipe that acts as an electrode rod for generating an electrostatic electric field in the injection sleeve and jets the powder into the injection sleeve. Since the ejection tube is provided with a plurality of powder ejection ports in the axial direction for ejecting powder toward the lower part in the injection sleeve, the powder ejection tube generates an electrostatic electric field in the injection sleeve, The powder flowing inside can be ejected toward the lower side of the injection sleeve, and the powder can be electrostatically applied only to the lower part of the injection sleeve.

  A specific preferred embodiment of the powder jet port includes a mode in which the powder jet port is formed downward or obliquely downward on the peripheral wall of the powder jet pipe. In this aspect, more preferably, a plurality of the powder jet outlets are provided in the axial direction of the powder jet pipe, and the powder jet pipe is provided in a direction opposite to the powder supply direction from the downstream side of the powder jet pipe. Back pressure air is sprayed toward the surface, and back pressure air injection means that can set the range of the gas wall formed in the powder injection pipe by the back pressure air is provided in the lower part of the inner surface of the injection sleeve substantially in the axial direction. The powder is uniformly applied.

  The powder ejection pipe may be configured to move in the axial direction of the injection sleeve while ejecting powder from the powder ejection port. According to this configuration, the powder ejected from the powder ejection port can be applied substantially uniformly over the axial direction of the injection sleeve by the movement of the powder ejection tube.

Since the present invention is configured as described above, the following effects can be obtained.
First, it has a powder jet pipe that acts as an electrode rod for generating an electrostatic electric field in the injection sleeve and jets powder into the injection sleeve, and the powder jet pipe is directed to a lower part in the injection sleeve. Since a plurality of powder jet outlets for jetting powder are arranged in the axial direction, the powder jet pipe generates an electrostatic electric field in the injection sleeve, while the powder flowing inside is placed below the injection sleeve. The powder can be ejected toward the surface, and the powder can be electrostatically applied only to the lower portion of the injection sleeve.

  In addition, according to the present invention, it is possible to prevent the powder from being applied to a portion other than the contact surface with the molten metal, and the powder sprayed from the powder spray pipe is disposed at an unnecessary portion in the injection sleeve. It can be prevented that it adheres. As a result, the amount of powder flowing into the cavity can be reduced, so that the amount of powder mixed in the product can be almost eliminated, and the quality of the cast product can be improved. Also, the amount of powder used is reduced.

Moreover, it can prevent more reliably by the interference body that the powder injected from a powder injection tube flows into the upper surface side in an injection sleeve.
In addition, since the partition body is close to or in contact with the inner peripheral surface of the injection sleeve, a powder is prevented from flowing to the upper surface side in the injection sleeve in order to secure a substantially partitioned space on the lower side in the injection sleeve. It can be reliably prevented. Therefore, the amount of powder mixed into the product can be further reduced, for example, the amount of powder mixed into the product cut surface can be reduced to about 1/7 compared with the prior art. Can do.

  A gas layer like a so-called air curtain is formed in the upper space of the injection sleeve by the gas ejected from the gas ejection pipe. Therefore, the powder ejected from the powder ejection pipe toward the lower space is prevented from flowing into the upper space of the injection sleeve by the gas layer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a part of a die casting machine A provided with a powder coating apparatus 1 according to the present invention. This die casting machine A is known in which a molten metal supplied from the hopper A1 into the injection sleeve A3 through the pouring port A2 is injected and cast into the cavity A4 indicated by the phantom line by the piston movement of the plunger tip A5. The powder coating apparatus 1 is provided on the rear side of the pouring spout A2. The powder coating apparatus 1 includes a cylinder mechanism 10 that is supported obliquely on the rear side of the pouring port A2, a substantially tubular powder coating unit 20 that is pivotally supported by a slide portion 12 of the cylinder mechanism 10, A support portion 30 and the like for supporting the powder coating unit 20 and guiding it into the pouring port A2 are provided.

  The cylinder mechanism 10 is a so-called rodless cylinder that linearly reciprocates the slide portion 12 with respect to the cylinder body 11 that is supported obliquely by a drive medium such as hydraulic pressure or pneumatic pressure. The powder coating unit 20 is pivotally supported via the shaft.

  The powder coating unit 20 includes a powder jet pipe 21 that is a conductive metal pipe bent in a U-shape, and jets powder to be circulated inside the powder jet pipe 21 from the front end surface and the outer peripheral surface. And a function as an electrode rod for generating an electrostatic electric field in the injection sleeve A3 by a high voltage generator (not shown).

  The support portion 30 is a member that is disposed on the rear end side (right end side in the illustrated example) of the pouring port A2 in the injection sleeve A3, and that guides the pouring unit A2 into the pouring port A2 while supporting the powder application unit 20 by its upper surface. According to a preferred example of the present embodiment, the roller is fixed so that the frictional resistance with the powder coating unit 20 is reduced and the powder coating unit 20 is smoothly guided into the pouring port A2. Become.

  Thus, according to the above-described configuration, when the slide portion 12 of the cylinder mechanism 10 descends obliquely along the cylinder body 11, the powder application unit 20 is supported by the support portion 30 at the tip side portion. While being swung upward, it is inserted into the injection sleeve A3 from the pouring port A2, and the distal end side portion is disposed on the substantially axial center of the injection sleeve A3. Thereafter, the powder coating unit 20 ejects the powder flowing inside while generating an electrostatic electric field, and electrostatically coats the powder on the inner surface of the sleeve A3.

  Next, the configuration of the powder coating unit 20 and the powder ejection action will be described in detail. The powder application unit 20 includes a powder jet pipe 21 bent into a U-shape and a plurality of first to third back pressures disposed on the outer peripheral surface of the powder jet pipe 21 at predetermined intervals. It consists of the injection means 22a, 22b, 22c and the interference body 23 surrounding the upper half part side of the powder injection pipe 21 (see FIG. 2). 2 and 5, the first to third back pressure injection means 22a, 22b, and 22c are arranged in series at the upper end of the outer peripheral surface of the powder injection pipe 21, thereby simplifying the illustration. In practice, these back pressure injection means 22 are actually arranged at a predetermined angle in the circumferential direction of the powder injection pipe 21 as shown in FIG. 3 in order to avoid mutual interference. Yes.

  The powder ejection pipe 21 bends a pipe material made of a conductive metal material into a U-shape, and at a portion of the outer peripheral surface thereof that does not interfere with the first to third back pressure ejection means 22a, 22b, 22c, A plurality of ejection rods 21a are formed in the circumferential direction and the axial direction, and a distal end ejection opening 21b is formed at the distal end so that powder can be ejected. According to a preferred example of the present embodiment, the powder ejection rod 21a is disposed at two positions 45 degrees downward on the left and right of the vertical center line and at a predetermined interval in the axial direction as shown in FIG. The partial powder coating means for partially coating the powder sprayed from the powder spray pipe 21 only on the contact surface with the substantially molten metal on the inner surface of the injection sleeve A3. Is configured.

  The 1st-3rd back pressure injection means 22a, 22b, 22c is arrange | positioned in order from the most advanced side of the powder injection pipe 21 to the rear-end side. That is, according to the illustrated example, the first back pressure injection means 22a is arranged on the most distal side of the powder injection pipe 21, and the second back pressure injection means 22b is connected to the first back pressure injection means 22a. The third back pressure injection means 22c is arranged upstream from the second back pressure injection means 22b with a predetermined interval. The third back pressure injection means 22c is arranged upstream from the second back pressure injection means 22b.

  Each of the first to third back pressure injection means 22 a, 22 b, and 22 c is supplied with air pressurized by an air compressor or the like (not shown) along the outer surface of the powder injection pipe 21. A back pressure air circulation pipe p1 that circulates in the front end direction and communicated with the front end side of the back pressure air circulation pipe p1, and the air in the back pressure air circulation pipe p1 is pulverized from the downstream side in the powder ejection pipe 21. It consists of a back pressure injection nozzle p2 which injects in the direction opposite to the body supply direction.

  Here, the operation of each of the first to third back pressure injection means 22a, 22b, and 22c will be described in detail. As shown in FIG. 4, each back pressure injection means 22a (22b, 22c) has a back pressure. Air in the direction opposite to the flow direction of the powder is jetted into the powder jet pipe 21 through the jet nozzle p2. Then, the injected air collides with the powder flow, and the air wall q is formed in the powder ejection pipe 21 by the air. The range w of the gas wall q is a range between the collision surface q1 and the back pressure injection nozzle p2 when the gas injected from the back pressure injection nozzle p2 collides with the powder flow. In addition, the position of the collision surface q1 at that time is determined in such a manner that the powder ejection amount 21a in which the powder ejection amount is extremely reduced when experimentally measuring the amount of powder ejection from the plurality of powder ejection chambers 21a. Further, it is closer to the powder supply side and in the vicinity of the powder ejection nozzle 21a.

  The range w of the gas wall q is the pressure of the air injected from the back pressure injection nozzle p2 and the pressure of the powder flowing in the powder injection pipe 21 (specifically, the pressure of the air that is the powder carrier) ) And the pressure ratio (air pressure / powder pressure), that is, if the pressure ratio is large, the range w of the gas wall q is large, and if the pressure ratio is small, the range w of the gas wall q is small. Become. In the present embodiment, the pressure ratio (air pressure / powder pressure) is set in the range of about 1.5 to 3, preferably about 2.5.

  The powder flowing in the powder ejection pipe 21 collides with the gas wall q, so that the density of the portion x close to the gas wall q is increased. Then, the dense portion x of the powder gradually moves at a substantially constant speed in the powder downstream direction (left direction in the drawing) by stopping the injection of air from the back pressure injection nozzle p2.

  The air control will be described more specifically. For example, an electric valve (not shown) is provided on the air supply source side of the back pressure air circulation pipe p1, and the electric valve is opened and closed by ON / OFF control of the electric valve. The air injection from the back pressure injection nozzle p2 may be switched from ON to OFF. Even when the air ejection from the back pressure injection nozzle p2 is suddenly stopped by the ON / OFF control, the portion x where the powder in the powder ejection pipe 21 is concentrated moves rapidly in the downstream direction. Without any effect, the powder jet pipe 21 gradually moves downstream at a substantially constant speed due to the influence of pipe friction or the like.

  On the other hand, the powder ejection pipe 21 ejects powder from each powder ejection nozzle 21a on the powder supply source side of the gas wall q. At this time, the amount of powder ejected is the largest in the powder ejection rod 21a1 close to the dense portion x of the powder, and the powder ejection rod 21a2 on the powder supply source side further than the powder ejection rod 21a1. It decreases gradually as you go to 21a3. When the air jet from the back pressure injection nozzle p2 is stopped by the ON / OFF control, the dense portion x of the powder gradually moves downstream at a substantially constant speed as described above. Therefore, as the movement proceeds, the powder ejection nozzle 21a1, which ejects the largest amount of powder, and the powder ejection cylinders 21a2, 21a3,. It will move to the powder ejection rod 21a on the downstream side.

  According to the present embodiment, as described above, by turning off the air injection from the back pressure injection nozzle p2 from ON to OFF, the powder injection nozzles 21a1, 21a2, 21a3. Is gradually shifted in the downstream direction, but the same effect can be obtained by gradually decreasing the pressure of the air injected from the back pressure injection nozzle p2. Further, if the injection of air from the back pressure injection nozzle p2 is switched from OFF to ON, or if the pressure of the air injected from the back pressure injection nozzle p2 is gradually increased, the powder injection for discharging the powder is performed. It is also possible to gradually move the outlets 21a1, 21a2, 21a3,.

  In addition, according to the illustration of FIG. 4, the solid line indicating the powder ejection is illustrated in the powder ejection rod 21 a on the downstream side (left side in the drawing) from the powder ejection rod 21 a 1 having the largest powder ejection amount. In actuality, however, a slight amount of powder is ejected also in the powder ejection rod 21a downstream of the powder ejection rod 21a1 in the figure due to the occurrence of turbulent flow in the powder ejection tube 21 and the like.

  The first to third back pressure injection means 22a, 22b, and 22c acting as described above are arranged at predetermined intervals along the longitudinal direction of the powder injection pipe 21, as shown in FIG. The installation interval, that is, the interval between the back pressure injection nozzles p2 and p2, is set with the range w of the gas wall q described above as a guide. In the illustrated example, the interval between the back pressure injection nozzle p2 of the first back pressure injection means 22a and the back pressure injection nozzle p2 of the second back pressure injection means 22b is w1, and the back of the second back pressure injection means 22b. The interval between the pressure injection nozzle p2 and the back pressure injection nozzle p2 of the third back pressure injection means 22c is w2, and these intervals w1 and w2 indicate the range of the gas wall q formed by the back pressure injection nozzle p2, respectively. It is set as a guide. Further, the range indicated by the symbol w3 in the figure indicates a range in which the powder ejection nozzle 21a is provided on the rear end side of the powder application unit 20, so that the powder can be applied to the rear end in the injection sleeve A3. It is set. The plurality of powder ejection rods 21a of the powder ejection pipe 21 are disposed within the above range w1 to w3.

  Further, as shown in FIG. 3, the interference body 23 includes a surrounding portion 23a surrounding the upper half portion of the powder ejection pipe 21 and a horizontal portion extending substantially horizontally from both ends of the surrounding portion 23a. It consists of a plate portion 23b, is provided continuously from the tip of the powder ejection pipe 21 to the range having the substantially powder ejection nozzle 21a, and is supported on the outer peripheral surface of the powder ejection pipe 21. The interference body 23 cooperates with the plurality of powder ejection pipes 21a in the powder ejection pipe 21 to cause the powder ejected from the powder ejection pipe 21 to substantially melt on the inner surface of the injection sleeve A3. A partial powder coating means for partially coating is formed only on the contact surface.

  When the interference body 23 is inserted into the injection sleeve A3 together with the powder ejection pipe 21, the interference body 23 is arranged so as to partition the space in the injection sleeve A3 substantially vertically, and the powder ejected from the plurality of powder ejection nozzles 21a. The body is prevented from flowing upward in the injection sleeve A3. That is, as shown in FIG. 7, in the interference body 23, the powder injected obliquely downward from the plurality of powder ejection nozzles 21a of the powder ejection pipe 21 wraps around the upper side in the injection sleeve A3. Is preventing. The powder ejected from the plurality of powder ejection nozzles 21a into the injection sleeve A3 is hardly applied to the upper side of the inner peripheral surface of the injection sleeve A3, and mainly the lower side in the injection sleeve A3, that is, It will be applied to the area where the molten metal flows.

  The width dimension of the interference body 23 (width dimension in the radial direction of the injection sleeve A3) is appropriately set according to the range in the circumferential direction of the molten metal (in the circumferential direction of the injection sleeve A3) when the molten metal flows into the injection sleeve A3. Is done. That is, when the circumferential range of the molten metal is relatively wide, the width dimension is set to be narrow so that the amount of powder flowing upward in the injection sleeve A3 is increased, and the circumferential range of the molten metal is set. Is relatively narrow, the width dimension is set wide so as to reduce the amount of powder that flows upward in the injection sleeve A3.

  Next, a preferable control example in which the gas injection by the first to third back pressure injection units 22a, 22b, and 22c is controlled to be turned ON / OFF in order in the axial direction will be described in detail (FIGS. 5 and 6). reference). First, the powder application unit 20 is inserted into the injection sleeve A3, and is arranged so that the tip side portion thereof is substantially coaxial with the injection sleeve A3. Then, the powder is supplied into the powder ejection pipe 21 at a pressure of about 0.2 MPa for 8 seconds, and simultaneously with the start of the supply, air injection by the third back pressure injection means 22c is started. The air injection by the third back pressure injection means 22c is continued for about 2 seconds at a pressure of about 0.5 MPa. Then, a gas wall q is formed in the range w3 in the powder ejection pipe 21, and a portion x where the density of the powder is high in the vicinity of the gas wall q on the powder supply side of the gas wall q. Is formed (see FIG. 5A).

  Next, the gas injection by the second back pressure injection means 22b is started at the same time as the gas injection by the third back pressure injection means 22c is stopped. The gas injection by the second back pressure injection means 22b is continued for about 2 seconds at a pressure of about 0.5 MPa. Then, a gas wall q is formed in the range w2 in the powder jet pipe 21, and the dense portion x of the powder is moved in the range w3 at a substantially constant speed so as to gradually approach the gas wall q. Move downstream. With this movement, powder is sequentially ejected from the plurality of powder ejection nozzles 21a in the range w3 from the upstream side (right side in the figure) to the downstream side (left side in the figure). 5 (b)).

  Furthermore, the gas injection by the first back pressure injection means 22a is started simultaneously with the gas injection by the second back pressure injection means 22b being stopped. The gas injection by the first back pressure injection means 22a is continued for about 4 seconds at a pressure of about 0.3 MPa. Then, a gas wall q is formed in the range w1 in the powder ejection pipe 21, and the dense portion x of the powder downstream of the range w2 at a substantially constant speed so as to gradually approach the gas wall q. Move in the direction. With this movement, the powder is sequentially ejected from the plurality of powder ejection nozzles 21a in the range w2 from the upstream side toward the downstream side. In addition, the powder ejection from the plurality of powder ejection nozzles 21a in the range w3 is continued (see FIG. 5C).

  Finally, at the same time as the gas injection by the first back pressure injection means 22a is stopped, the supply of powder from the powder supply source into the powder ejection pipe 21 is also stopped, Is supplied with cleaning air containing no powder at a pressure of about 0.2 MPa for about 3 seconds. Then, the dense portion x of the powder gradually moves in the downstream direction in the range w1, and along with the movement, the plurality of 21a in the range w1 in order from the upstream side to the downstream side. Goes out. And the dense part x of powder is finally discharged | emitted from the front-end | tip ejection opening part 21b. Note that the powder ejection from the plurality of powder ejection nozzles 21a in the ranges w2 and w3 is continued until the cleaning air reaches the powder ejection tank 21a on the most upstream side (FIG. 5C). reference). Then, after the inside of the powder jetting nozzle 21a is cleaned by the cleaning air, the powder application unit 20 is extracted from the injection sleeve A3.

  The air jetting time of each of the first to third back pressure jetting means 22a, 22b, and 22c is set so that the dense portion x of the powder moves substantially continuously in the range w3, w2, and w1. It is.

  Thus, according to the powder coating apparatus 1, the dense portion x of the powder moves in the powder jet pipe 21 from the upstream side to the downstream side of the powder jet pipe 21 at a substantially constant speed. The subsequent portion where the powder density is lower than x moves from the upstream side to the downstream side of the powder ejection pipe 21 at a substantially constant speed. Accordingly, in the lower side of the inner circumferential surface of the injection sleeve A3, that is, in the portion where the molten metal flows, a coating film is formed in the ranges w3, w2, and w1 with a substantially uniform thickness over the axial direction. Further, in the range on the tip side (the left side in the drawing) of the inner peripheral surface of the injection sleeve A3 from the range w3, w2, and w1, the range w3 is due to the powder finally discharged from the tip ejection opening 21b. , W2 and w1, and a coating film is formed with a substantially uniform thickness.

Note that the values described above for the air pressure, the air ejection time, the powder supply pressure of the powder supply source, the powder supply time, etc. of each of the first to third back pressure injection means 22a, 22b, 22c (see FIG. 6). The value shown shows a particularly preferable example, but is adjusted as appropriate so that the film thickness of the powder actually applied to the inner peripheral surface of the injection sleeve A3 becomes substantially constant.
That is, since a turbulent flow is generated between the inner peripheral surface of the injection sleeve A3 and the outer peripheral surface of the powder jet pipe 21 during the coating operation, for example, the amount of powder jetted from each powder jetting nozzle 21a is substantially reduced. Even if it is controlled to be constant, the film thickness of the powder applied to the inner peripheral surface of the injection sleeve A3 may not be substantially constant. Therefore, the air pressure, the air ejection time, the powder supply pressure of the powder supply source, the powder supply time, etc. of each of the first to third back pressure injection means 22a, 22b, 22c are actually applied injections. The film thickness of the powder on the inner peripheral surface of the sleeve A3 is experimentally measured, and the film thickness is set to be substantially constant.

  In the above embodiment, the interference body 23 is the above-described one as long as it prevents the powder ejected from the powder ejection nozzle 21a of the powder ejection pipe 21 from flowing above the injection sleeve A3. It is not limited to. Below, the other aspect of the interference body 23 is demonstrated. In addition, in the aspect shown below, it is set as the structure which excluded the said back pressure injection means 22, However, It is good also as a structure which added the said back pressure injection means 22 as needed. Moreover, in the aspect shown below, about the site | part substantially the same as the said embodiment, while attaching the same code | symbol, the detailed description which overlaps is abbreviate | omitted.

  An interfering body 40 shown in FIG. 8 includes a powder ejection pipe 41 inserted in the injection sleeve A3 in the axial direction, and the powder ejection pipe 41 so as to sandwich the powder ejection pipe 41 at a substantially horizontal center. The two auxiliary pipes 42 and 42 fixed substantially in parallel on both sides of the above-described interference pipes, and the powder jet pipe 41 and the auxiliary pipe 42 partition the space in the injection sleeve A3 into the upper and lower sides, thereby the above-described interference body. Similarly to the case 23, the sprayed powder is prevented from flowing to the upper side of the injection sleeve A3.

  The powder ejection pipe 41 is a tube configured substantially in the same manner as the powder ejection pipe 21 of the powder coating unit 20, and the powder ejection pipe with the ejection direction directed to the lower part in the injection sleeve A3. A plurality of 41a are provided in the circumferential direction and the axial direction. In addition, the auxiliary pipe 42 is provided with, for example, a powder jet outlet (not shown) facing the lower part in the injection sleeve A3, thereby increasing the amount of powder jetted by the powder jet pipe 41. Or may be used as a tube for the powder, or by providing a suction port (not shown) for sucking powder toward the upper part in the injection sleeve A3, the powder ejected from the powder ejection pipe 41 It may be used to more reliably prevent the body from flowing upward in the injection sleeve A3.

  Further, the interference body 50 shown in FIG. 9 is a tubular body having a rectangular cross section inserted in the injection sleeve A3 in the axial direction. Like the interference body 23, the powder flows to the upper side of the injection sleeve A3. It has both the effect of preventing and the effect of ejecting powder toward the lower part in the injection sleeve A3 as in the case of the powder ejection pipe 21. The interference body 50 is formed with a plurality of powder ejection nozzles 51a in the width direction and the axial direction on the lower surface thereof, in which powder supplied from a powder supply source (not shown) is distributed, Powder is ejected from the plurality of powder ejection nozzles 51a and applied to the lower part in the injection sleeve A3. And the interference body 50 becomes an obstacle of the powder which tends to flow upward in the injection sleeve A3, thereby preventing the powder from being applied to the upper part in the injection sleeve A3.

  The partial powder coating means for partially coating the powder sprayed from the powder spray pipe only on the contact surface with the molten metal on the inner surface of the injection sleeve A3 is limited to the configuration described above. In addition, the following configuration may be adopted.

  10 and 11 includes a powder jet pipe 61 inserted from the cavity side opening A3a of the injection sleeve A3, and a partition 62 fixed to the distal end side of the powder jet pipe 61. A suction pipe 63 fixed substantially parallel to the upper surface of the powder jet pipe 61 in the axial direction, and the powder jet pipe 61, the partition 62, and the suction pipe 63 are axially arranged in the injection sleeve A3. It is comprised so that it may move.

  The powder ejection pipe 61 is provided with a plurality of powder ejection nozzles 61 a 1 for ejecting powder downward toward the space in the partition 62. The powder jet pipe 61 is configured such that the front part 61a having the plurality of powder jets 61a1 is made of a metal tube, and the rear part 61b is made of a flexible tube. It can be easily extracted into the cavity side space.

  Further, the partition 62 is disposed in a downward direction at both ends in the axial direction of the horizontal partition wall 62a and a horizontal partition wall 62a disposed so as to partition a part of the space in the injection sleeve A3 vertically. The two vertical partition walls 62b and 62b are integrally formed, and close to or in contact with the inner peripheral surface of the injection sleeve A3 to secure a substantially partitioned space on the lower side in the injection sleeve A3.

  The horizontal partition wall 62a has both ends in the horizontal direction intersecting with the axis of the injection sleeve A3 in contact with the inner peripheral surface of the injection sleeve A3, and substantially in the center between the both ends and substantially the axis of the injection sleeve A3. The powder jet pipe 61 and the suction pipe 63 are fixed so as to be parallel.

  The vertical partition wall 62b is a plate-like member that is semicircular when viewed from the front, and its upper side portion is connected and fixed to the lower surface of the horizontal partition wall 62a, and the outer peripheral end portion of the semicircular portion is the lower half portion of the injection sleeve A3. A slight gap S is ensured in the vicinity. The gap S rubs the powder applied to the inner peripheral surface of the injection sleeve A3 by the outer peripheral end of the vertical partition wall 62b when the vertical partition wall 62b is moved in the axial direction in the injection sleeve A3. There is no such thing.

  Further, the suction pipe 63 is disposed with the suction port 63a at the tip thereof communicating with the lower space in the partition 62, and the rear portion is formed of a flexible tube, whereby the injection sleeve A3. It can be easily extracted to the outer cavity side space. The suction pipe 63 sucks the atmosphere of the space when the powder is ejected from the powder ejection rod 61 a 1 of the powder ejection pipe 61 to the space in the partition 62. That is, if the powder is ejected from the powder ejection rod 61a1 to the space in the partition 62 without performing suction by the suction pipe 63, the atmosphere in the partition 62 is increased in pressure, so that the partition There is a concern that the powder in the body 62 leaks out of the partition 62 and wraps around the upper surface side in the injection sleeve A3. The suction pipe 63 sucks the atmosphere in the partition body 62 to prevent the pressure in the partition body 62 from rising due to the ejection of powder, and as a result, the powder leaks from the partition body 62 to the outside of the partition body 62. In addition, it is possible to more reliably prevent the powder from being applied to the upper portion of the injection sleeve A3.

  In the figure, reference numeral 64 denotes a support bar that supports the powder ejection pipe 61, the partition 62, the suction pipe 63, and the like. The support bar 64 is pivotally attached so that the rear side 64b is bent upward with respect to the front side 64a. The support rod 64 makes it possible to insert and remove the powder ejection pipe 61, the partition 62, the suction pipe 63, and the like into and out of the injection sleeve A3 by using a limited space on the cavity side. .

  Next, an operation for applying powder in the injection sleeve A3 using the powder applying apparatus 60 having the above-described configuration will be described. First, the powder application device 60 is inserted from the cavity side opening A3a of the injection sleeve A3, and the partition 62 on the distal end side of the powder ejection pipe 61 is brought into contact with or close to the distal end surface of the plunger tip A5. In this state, when the powder is ejected from the plurality of powder ejection nozzles 61a1 into the partition 62, suction by the suction pipe 63 is started almost simultaneously. Then, immediately after the ejection and suction, the powder coating device 60 is moved to the cavity side in the injection sleeve A3 and finally extracted from the cavity side opening A3a. Therefore, according to the powder application device 60, the powder ejected from the plurality of powder ejection nozzles 61a1 is applied substantially uniformly over the axial direction only on the lower surface in the injection sleeve A3.

  Incidentally, according to the illustrated powder coating apparatus 60, the axial length of the partition 62 is injected in order to facilitate insertion and extraction from the cavity side opening A3a of the injection sleeve A3. Although it is significantly shorter than the axial length of the sleeve A3, the axial length of the partition 62 may be longer than that of the illustrated example, or may be approximately the same as the axial length of the injection sleeve A3. Is possible.

  Further, the powder coating apparatus 70 shown in FIG. 12 is fixed substantially parallel to the powder jet pipe 71 having the same configuration as the powder jet pipe 21 and the upper surface of the powder jet pipe 71 in the axial direction. And a gas ejection pipe 72.

  The powder ejection pipe 71 is provided with a plurality of powder ejection nozzles 71a for ejecting powder on the peripheral wall in substantially the same manner as the powder ejection pipe 21 described above. A plurality of these powder jetting nozzles 71a are disposed in the injection sleeve A3 along the circumferential direction and the axial direction of the powder jetting pipe 71 while being directed to the lower part of the injection sleeve A3. The gas ejection pipe 72 has a plurality of gas ejection rods 72a that eject gas toward the upper space in the injection sleeve A3 in the axial direction on the peripheral wall. As the gas ejected from the gas ejection pipe 72, an inert gas such as air or nitrogen is used.

  According to the powder coating apparatus 70 having the above configuration, a gas layer like a so-called air curtain is formed by the gas ejected from the gas ejection pipe 72 in the upper space portion of the injection sleeve A3. Therefore, the powder ejected from the powder ejection pipe 71 is prevented from flowing into the upper space in the injection sleeve A3 by the gas layer, and is attached only to the lower part in the injection sleeve A3.

  Note that, according to the illustrated example, the gas ejection rod 72a is drilled substantially directly upward, but by ejecting gas toward the upper space in the injection sleeve A3, the upper space in the injection sleeve A3. If it has an effect of forming a gas layer, it may be drilled in a substantially horizontal direction (see FIG. 13) or obliquely upward.

  Further, in the powder coating device 70, the powder is injected by providing an interference body (not shown) having substantially the same configuration as the interference body 23 between the powder ejection pipe 71 and the gas ejection pipe 72. You may make it prevent more reliably that it flows into the upper side in sleeve A3.

  The powder coating device 70 may be configured to be inserted from the pouring port A2 in the injection sleeve A3 or may be configured to be inserted from the cavity side opening A3a in the injection sleeve A3. .

  1 to 5 and FIGS. 7 to 9, the partial powder application means including the powder ejection pipe 21, the interference body 23, the interference body 40, the interference body 50, and the like is used as the injection sleeve. Although the aspect which inserted from the pouring port A2 in A3 was illustrated, it is also possible to comprise the same partial powder application means so that it may be inserted from the cavity side opening part A3a in the injection sleeve A3.

  Next, the results of an experiment in which powder is applied to the injection sleeve A3 using the partial powder application unit will be described. First, by using the partial powder application means shown in FIGS. 2 to 7, the powder is applied in the injection sleeve A3, and the powder adhered to the upper part in the injection sleeve A3 and the injection sleeve A3. As a result of scraping the powder adhering to the lower part and comparing the amount of both of the scraped powders, the ratio (the amount of powder in the upper part / the amount of powder in the lower part) is approximately It was 10% or less. That is, the amount of powder attached to the upper part in the injection sleeve A3 could be about 10% or less of the amount of powder attached to the lower part.

  In addition, the results of a comparative experiment in which powder is applied to the injection sleeve A3 using the partial powder application unit shown in FIGS. 10 and 11 are shown below. FIG. 14 is a graph showing how much the powder mixing area ratio [%] (vertical axis) of the product cut surface varies depending on the powder application region (horizontal axis) in the sleeve. In addition, the powder mixing area ratio of the product cut surface is obtained by cutting the actually cast product, measuring the entire area of the cut surface and the area of the portion where the powder is mixed, and the ratio of both. Is calculated. Each of N1 and N2 in the figure shows a graph when powder is applied to substantially the entire inner surface of the injection sleeve A3 using a conventional powder coating apparatus. In the figure, each of n1 and n2 shows a graph when the powder is applied only to the lower part in the injection sleeve A3 using the partial powder application means shown in FIGS. From the result of the comparative experiment, when the powder is applied only to the lower part in the injection sleeve A3 by using the partial powder application means, the powder is applied to substantially the entire inside of the injection sleeve A3. The amount of powder mixed into the product cut surface could be reduced to about 1/7.

The schematic diagram which shows an example of the die-casting machine provided with the powder coating device concerning this invention. The principal part sectional drawing which shows an example of the powder application unit provided with the powder application apparatus concerning this invention. The cross-sectional view of the powder coating unit. The principal part expanded sectional view of the powder application unit. (A) thru | or (d) shows the principal part sectional drawing which shows the state which a powder flows in a powder ejection pipe | tube sequentially, and the interference body is abbreviate | omitted. Control time chart of the powder coating unit. The cross-sectional view which shows the state through which powder flows in the same powder ejection pipe. The cross-sectional view which shows the other aspect of an interference body. The cross-sectional view which shows the other aspect of an interference body. The longitudinal cross-sectional view which shows the other examples of the powder coating device concerning this invention. (11)-(11) sectional view taken on the line in FIG. The cross-sectional view which shows the other example of the powder coating device concerning this invention. The cross-sectional view which shows the other example of a gas ejection pipe. The graph which shows the result of a comparative experiment.

Explanation of symbols

1, 60, 70: Powder coating apparatus 21, 41, 61, 71: Powder ejection pipe 21a, 41a, 51a, 61a1: Powder ejection rod 23, 40, 50: Interference body 62: Partition body 72: Gas ejection Tube A3: Injection sleeve

Claims (3)

In a powder coating apparatus that electrostatically coats powder on the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus,
A powder jet pipe made of a conductive metal tube, inserted into the injection sleeve, acts as an electrode rod for generating an electrostatic electric field in the injection sleeve, and jets the powder into the injection sleeve. Prepared,
The powder jet pipe is provided with a plurality of powder jet outlets for jetting the powder toward the lower part in the injection sleeve arranged in the substantially horizontal direction, and the powder jet outlet An apparatus for applying powder to an inner surface of an injection sleeve , comprising: an interference body that prevents the powder ejected from the fluid from flowing upward in the injection sleeve. In a powder coating apparatus that electrostatically coats powder on the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus,
A powder jet pipe made of a conductive metal tube, inserted into the injection sleeve, acts as an electrode rod for generating an electrostatic electric field in the injection sleeve, and jets the powder into the injection sleeve. Prepared,
The powder ejection pipe includes a plurality of powder ejection ports that eject the powder toward a lower portion in the injection sleeve arranged in the substantially horizontal direction, and the powder injection pipe is disposed in the injection sleeve. A partition that secures a substantially partitioned space on the lower side in the injection sleeve in proximity to or in contact with the peripheral surface, and in the space from the powder jet port toward the lower part in the injection sleeve; powder coating apparatus to y de sleeve inner surface you characterized by ejecting the powder. In a powder coating apparatus that electrostatically coats powder on the inner surface of an injection sleeve arranged in a substantially horizontal direction in a casting apparatus,
A powder jet pipe made of a conductive metal tube, inserted into the injection sleeve, acts as an electrode rod for generating an electrostatic electric field in the injection sleeve, and jets the powder into the injection sleeve. Prepared,
The powder jet pipe is provided with a plurality of powder jet outlets for jetting the powder toward the lower part in the injection sleeve arranged in the substantially horizontal direction, and the powder jet pipe in the injection sleeve powder coating apparatus to y de sleeve inner surface you characterized by being provided with a gas ejection pipe having a gas outlet for ejecting a gas toward the upper space.

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