JP2010227985A - Centrifugal casting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal casting method by which a molten metal pouring tube is inserted without trouble into a cylindrical mold of a centrifugal molding device. <P>SOLUTION: A belt-like laser beam that is emitted from a light emitting element 46 and received by a light receiving element 48 intersects at 90° with a belt-like laser beam that is emitted from a light emitting element 47 and received by a light receiving element 49, in a plane orthogonal to the axial line of a molten metal pouring tube 20. Then, the axial line of the pouring tube 20 under the assumption of no sagging occurring is set in a manner coinciding the center of a square detection region that is formed by the intersecting. If the pouring tube 20 is sagging by gravity, the center of the detection region is separated from the axial line of the pouring tube 20, which reduces a light quantity shut off by the pouring tube 20, with a received light quantity increased in the light receiving elements 48, 49. By distributing this increment of the received light quantity to the X direction component and the Y direction component, the position is known of the axial line of the pouring tube 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a centrifugal casting method using a pouring pipe (ladle).

Centrifugal casting is known as a casting method for a cylinder sleeve or the like disposed in an engine bore.
This centrifugal casting method is a casting method in which molten metal is injected into a cylindrical mold rotating at high speed via a pouring pipe, and the molten metal is pressed against the inner surface of the cylindrical mold by centrifugal force.

In the centrifugal casting method, a cylindrical mold is generally arranged in the horizontal direction. When the molten metal is supplied from one end into the cylindrical mold arranged in the horizontal direction, the Al alloy or the like has a high solidification rate, so that the molten metal may not reach the other end sufficiently. For this reason, patent documents 1-4 are known as prior art which used the long thing as a pouring pipe, and the pouring spout reached the inner part in a cylindrical metal mold | die.

In Patent Documents 1 and 2, a clamping plate is attached to the tip and middle of a long pouring pipe, and a penetration support plate through which the pouring pipe passes is provided between the clamping plates, and surrounds the pouring pipe. In this way, a structure is disclosed in which four rod heaters are passed through and supported on the sandwiching plate and the through support plate so as to surround the pouring pipe.

In Patent Document 3, when casting a two-layer pipe by a centrifugal casting method, a thermometer for measuring the inner surface temperature of the molten metal and attaching a heater to the outer peripheral portion of the insert portion of the long pouring pipe is poured. A structure provided in a pipe has been proposed.

In Patent Document 4, the amount of molten metal poured from the pouring pipe is made uniform along the length direction of the mold by moving the carriage on which the mold is placed without moving the pouring pipe (trough). I try to make it.

JP 2008-221312 A JP 2008-223699 A Japanese Patent Laid-Open No. 7-227660 Japanese Patent No. 4071004

  By using the long pouring pipe described above, the pouring port can be inserted into the cylindrical mold, so if the pouring pipe is poured while moving in the axial direction of the cylindrical mold, In the cylindrical mold, pouring can be made evenly along the axial direction.

  However, since the long pouring pipe is supported in a cantilever state and the molten metal is heavy at a high temperature, the tip hangs down. If the amount of dripping is large, the pouring pipe cannot be inserted into the cylindrical mold. In Patent Documents 1 and 2 described above, since the periphery of the pouring pipe is surrounded by a rod-shaped heater, the amount of dripping is small, but there is a disadvantage that the overall diameter becomes large.

  The pouring pipes disclosed in Patent Documents 3 and 4 are thin and long, but no consideration is given to dripping of the pouring pipes. In particular, since the dripping amount changes for each shot depending on the preheating condition of the pouring pipe and the pouring temperature, it is not possible to determine the dripping amount in advance and correct the amount to pour hot water.

In order to solve the above problems, the centrifugal casting method according to the present invention measures the amount of dripping of a pouring pipe inserted into a cylindrical mold and performs pouring, and the insertion angle of the pouring pipe is based on the measurement result. After the correction, the pouring pipe was inserted into the cylindrical mold and the molten metal was supplied from the pouring pipe.
In order to insert the pouring pipe into the cylindrical mold, it is necessary to make the insertion direction of the pouring pipe coincide with the axis of the cylindrical mold installed in a substantially horizontal state. Either before or after measuring the dripping amount of the pouring pipe. However, if it is made to correspond to an axis before measuring, since a pouring pipe can be inserted immediately after a measurement, accuracy will improve.

The pouring pipe may be provided with a pouring port at the tip, but a pouring pipe formed with a slit capable of inflow and outflow of molten metal along the length direction has a high solidification rate. It is particularly preferable in the case of Al—Si molten metal. That is, in this case, it is inserted into a cylindrical mold with the slit facing up, and then the molten metal in the pouring pipe is turned by rotating the pouring pipe around the axis and directing the slit downward. It can supply simultaneously along the length direction of a cylindrical metal mold | die. As a result, the molten metal can be rapidly cooled to form fine Si crystals, and the wear resistance can be greatly improved.

Further, as a means for measuring the amount of dripping of the pouring pipe, an analysis of a camera image can be considered. However, when measuring an object that glows red, the contour of the image may become unclear. It is preferable to irradiate the pouring tube with two different belt-shaped laser beams. In this case, the two strip laser beams may be crossed or separated in the front-rear direction. As the laser beam used for measurement, a green laser beam is suitable because the measurement object is red-hot.

Further, it is conceivable that the two belt-like laser light emitting devices are attached to a frame that moves along the length direction of the pouring pipe. By setting it as such a structure, not only the dripping amount of a pouring pipe but the whole shape of a pouring pipe can be measured.

According to the present invention, since the amount of dripping of the pouring pipe is measured immediately before the pouring pipe is inserted into the mold for centrifugal casting, regardless of the preheating conditions and the pouring temperature of the pouring pipe, It is possible to know the amount of dripping pipe accurately.

And since the insertion angle to the cylindrical metal mold | die of a pouring pipe | tube is correct | amended based on the measurement result, a pouring pipe | tube can be reliably inserted in a cylindrical metal mold | die.

In addition, by forming a slit for inflow and outflow of the molten metal in the length direction of the pouring pipe, the molten metal can be supplied simultaneously in the entire length direction in the cylindrical mold of centrifugal casting. The solidification conditions can be the same over the entire length. As a result, a high-quality cast product can be obtained.

Side view of an example of an apparatus for carrying out the centrifugal casting method according to the present invention The enlarged view seen from the AA direction of FIG. The same figure as FIG. 2 explaining the operation of the measuring device Sectional drawing which shows the state which the pouring pipe entered into the cylindrical mold Cross section showing centrifugal casting

  Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the centrifugal casting apparatus includes a cylindrical mold 10, a pouring pipe 20, a robot 30 that moves the pouring pipe 20, and a measuring device 40 that measures dripping of the pouring pipe 20. In FIG. 1, the dripping of the pouring pipe 20 is exaggerated for easy understanding.

  The cylindrical mold 10 is supported on a pair of front and rear rollers 11 having a substantially horizontal shaft. The rollers 11 are fitted in grooves 12 formed in the circumferential direction of the cylindrical mold 10 to prevent the cylindrical mold 10 from moving in the axial direction during rotation.

  Further, at least one of the four rollers 11 is a drive roller that is rotated by a motor, and the rest are driven rollers.

  The cylindrical mold 10 has end plates 13 and 13 attached to both ends, and the pouring pipe 20 can be inserted into and removed from the cylindrical mold 10 through an opening formed in one end plate. In addition, a slit 21 is formed in the pouring pipe 20 along the length direction, and the slit 21 is for flowing in and out of the pouring pipe 20 and the length thereof is the length of the product to be cast. Is set approximately equal to.

  The robot 30 has a crank 32 at the tip of the articulated arm 31, and the pouring pipe 20 is attached to one end of the crank 32 in a cantilever state. The articulated arm 31 can support the pouring pipe 20 at an arbitrary position and posture within a predetermined range, and the crank 32 is rotatable around the axis of the tip arm of the articulated arm 31.

  The measuring device 40 is provided with a rail 42 on a base 41 and engages a frame 43 that reciprocates along the pouring pipe 20 in a standby state immediately before being inserted into the cylindrical mold 10 on the rail 42. Yes.

  In the frame 43, pillar portions 44 and 45 are erected on both sides of the pouring pipe 20, and light emitting elements 46 and 47 for emitting strip-shaped green laser light are attached to the upper portions of the pillar portions 44 and 45. Light receiving elements 48 and 49 for receiving the laser light are attached below 45.

The band-shaped laser light emitted from the light-emitting element 46 and received by the light-receiving element 48 and the band-shaped laser light emitted from the light-emitting element 47 and received by the light-receiving element 49 are within a plane orthogonal to the axis of the pouring pipe 20. It intersects at 90 °. Then, the axis of the pouring pipe 20 when it is assumed that no dripping has occurred is set so as to coincide with the center of a square detection region formed by intersecting as shown in FIG.

On the other hand, when the pouring pipe 20 hangs down by its own weight as shown in FIG. 3, the center of the detection area is separated from the axis of the pouring pipe 20, and the amount of light blocked by the pouring pipe 20 is reduced. The amount of light received at 48 and 49 increases. By allocating the increase in the amount of received light to the X direction component and the Y direction component, the position of the axis of the pouring pipe 20 can be known.

  Further, by knowing the position of the axis at each measurement position while moving the frame 43 along the pouring pipe 20, the overall shape of the pouring pipe 20 bent by its own weight can be known.

  In the above, in order to perform centrifugal casting, first, the robot 30 is operated to immerse the pouring pipe 20 in a molten metal holding furnace (not shown). For example, Al—Si-based molten metal is stored in the molten metal holding furnace, and when the molten metal pipe 20 is immersed, the molten metal is filled into the molten metal pipe 20 through the slit 21. In addition, the amount of the molten metal filled in the molten metal pipe 20 is adjusted by the immersion depth in the molten metal when the molten metal pipe 20 is inclined or in a vertical state.

  If the molten metal is filled in the molten metal pipe 20, the molten metal pipe 20 is taken out from the molten metal holding furnace with the slit 21 facing upward, moved to the vicinity of the cylindrical mold 10, and the molten metal pipe 20 is inserted. The direction is made to coincide with the axis (rotation center) of the cylindrical mold 10.

  From this state, using the measuring device 40 described above, the maximum amount of dripping or the entire shape of the pouring pipe 20 is measured, and the inclination of the pouring pipe 20 is adjusted according to the measurement result. For example, when the tip of the pouring pipe 20 is drooping, the articulated arm 31 is operated so that the tip of the pouring pipe 20 faces slightly upward, and the pouring pipe 20 is rotated along the axis in this state. The cylindrical mold 10 is inserted.

  Since the slit 21 faces upward as shown in FIG. 4 with the pouring pipe 20 in the cylindrical mold 10, the molten metal is held in the pouring pipe 20. Next, as shown in FIG. 5, the pouring pipe 20 is rotated around the axis so as not to change the position of the pouring pipe 20 in the cylindrical mold 10. Specifically, the articulated arm 31 of the robot 30 is moved so that the crank 32 rotates about the axis of the pouring pipe 20.

  Then, the slit 21 of the pouring pipe 20 is turned upside down in the cylindrical mold 10, and the molten metal held in the pouring pipe 20 is supplied from the slit 21 into the cylindrical mold 10.

Since the length of the slit 21 is set to be substantially equal to the length of the product to be cast, the molten metal for the entire length of the product is supplied into the cylindrical mold 10 at once, and the supplied molten metal is fed into the mold 10 by centrifugal force. Pressed against the inner peripheral surface and solidified into a product such as a cylinder sleeve.

  Thus, by supplying molten metal simultaneously along the full length of a product, the casting conditions in each part along the length direction become the same, and a high quality product can be cast.

  After the molten metal has solidified, the coating material is applied to the inner surface of the mold in advance, so that it can be easily taken out.

  In addition, although the apparatus which crosses a strip | belt-shaped laser beam was shown as the measuring apparatus 40 as an Example, it is not limited to this. Moreover, although the slit 21 was shown as a pouring port formed in the pouring pipe 20 as an Example, what provided the pouring port at the front-end | tip may be used.

The centrifugal casting apparatus provided with the pouring pipe according to the present invention can be applied to casting of a cylinder sleeve made of an Al-Si material.

10 ... Cylindrical mold, 11 ... Roller, 12 ... Groove, 13 ... End plate,
20 ... pour pipe, 21 ... slit,
30 ... Robot, 31 ... Articulated arm, 32 ... Crank,
DESCRIPTION OF SYMBOLS 40 ... Measuring apparatus, 41 ... Base, 42 ... Rail, 43 ... Frame, 44, 45 ... Column part, 46, 47 ... Light emitting element, 48, 49 ... Light receiving element.

Claims (3)

After measuring the amount of dripping of the pouring pipe inserted into the cylindrical mold and pouring the molten metal, and correcting the insertion angle of the pouring pipe based on this measurement result, the pouring pipe is connected to the axis of the cylindrical mold. A centrifugal casting method in which the molten metal is supplied from a pouring pipe by being inserted into a cylindrical mold along the line. 2. The centrifugal casting method according to claim 1, wherein the dripping amount of the pouring pipe is measured by irradiating the pouring pipe with two strip laser beams having different 90 ° directions. Law. 3. The centrifugal casting method according to claim 2, wherein the two belt-like laser light emitting devices having different 90 ° directions are attached to a frame that moves along the length direction of the pouring pipe. Casting method.