JP6075322B2 - Method and apparatus for removing sand from cylindrical castings - Google Patents

Description

  The present invention relates to a sand removal method and apparatus inside a cylindrical cast product.

  In sand mold casting, the sand mold including the cast product is placed on the cart together with the cast frame, and when the predetermined time has elapsed, the cart is removed and punched out to remove the sand mold from the cast frame, and the cast product with sand attached to the oscillating conveyor. The technique of putting and dropping sand is generally taken.

  However, in the case of a cylindrical cast product, since the sand in the cylinder is held from around by the cast product itself, it is difficult to fall even if it is placed on an oscillating conveyor, and if it is a raw sand mold with poor disintegration, Become more prominent. Although there is a method of removing sand by shot blasting, when shot blasting is simultaneously performed on a plurality of cast products, the cast products are easily damaged by collision between the cast products. In the barrel polishing method, as with shot blasting, the cast product is easily damaged.

  It is conceivable to avoid collision between castings by holding a cylindrical casting from the outside with a jig and shot blasting, but the shot ball does not hit the part held by the jig of the casting In addition to the fact that the sand of the portion does not fall, considerable consideration is required for positioning of the cast product, durability of the holding jig, scattering of the shot ball, and the like. Further, since a large amount of sand remains in the cylinder of the cast product, the amount of sand mixed into the shot ball increases, and the subsequent sand separation process becomes troublesome.

  On the other hand, in Patent Document 1, a pipe-shaped cast product is held on a support base, and the wire rope is advanced by a cylinder while being rotated by a motor, thereby causing the wire rope to enter the cast product to be moved into the cast product. It describes that the sand inside is dropped. In this way, if the sand in the cylinder of the cast product can be dropped, the cast product can be hung on the hanger using the opened cylindrical hole and shot blasted in that state.

Japanese Utility Model Publication No. 58-89166

  However, in the sand removal method described in Patent Document 1, it is necessary to take out the cast product from the sand mold by frame breakage (mold dispersal), and then set the cast product on the support base. Takes time to prepare. In particular, in the case of taking a large number of pieces, it is necessary to separate the individual cast products due to the frame variation, and then pick up the cast products one by one and set them on the support base, which makes it difficult to set the tact time on the production line.

  Therefore, the present invention makes it possible to remove the solid sand in the cylinder in a short time from the cylindrical cast product without causing a frame variation.

  In order to solve the above-described problems, the present invention is configured to pierce the sand mold with a hole passing through the inside of the cast product and insert a striking rod into the hole to crush and remove the sand in the cast product cylinder. This will be specifically described below.

The method for removing sand inside a cylindrical cast product presented here is a method for removing sand in the cylinder from a cylindrical cast product cast in a sand mold,
A sand mold containing the cast product is positioned below the sand mold punching device so that the axial direction of the cast product is vertical, a drilling step of drilling holes in the sand mold;
The sand mold after drilling is positioned below the in-cylinder sand crushing device, and comprises a sand removal step of crushing and removing the sand in the cylinder of the cast product,
The sand-type drilling device includes a drill for drilling,
In the drilling step, by lowering the drill while rotating, a hole passing through the cylinder of the cast product is drilled in the sand mold,
The in-cylinder sand crushing device is connected to a rotating shaft provided vertically by a flexible joint, and when the rotating shaft rotates, a rod for striking that is swung by the bending of the flexible joint. Prepared,
In the sand removal step, the sand in the cylinder of the cast product is crushed and removed by inserting the rod into the sand mold hole and rotating the rotating shaft to swing the rod.

Further, the sand removal device inside the cylindrical cast product presented here is a device for removing sand in the cylinder from the cylindrical cast product cast by the sand mold,
A transport device for supporting and transporting the sand mold containing the cast product so that the axial direction of the cast product is vertical;
A drill provided vertically for sand mold drilling, a driving means for rotating the drill, and an elevating means for raising and lowering the drill, and the sand mold including the cast product is positioned below the drill by the conveying device. A sand mold drilling device that lowers the drill while rotating the drill so that a hole passing through the inside of the cylinder of the cast product is drilled in the sand mold,
A striking rod connected to a vertical rotating shaft by a flexible joint and swung by the deflection of the flexible joint when the rotating shaft rotates, and a drive for rotating the rotating shaft And a lifting means for raising and lowering the rotating shaft, and when the sand mold is positioned below the in-cylinder sand crushing apparatus by the conveying device, the rod is lowered and inserted into the hole of the sand mold, An in-cylinder sand crushing device that rotates the rotating shaft and swings the rod so that sand in the cylinder of the cast product is crushed is provided.

  According to the present invention, sand in a cast product cylinder can be removed by drilling with a drill and striking from the inside with a striking rod without breaking the sand mold. In addition, the sand mold is positioned sequentially below the sand mold drilling device and the in-cylinder sand crushing device, and the sand in the cast product cylinder is removed by drilling with a drill and hitting from the inside with a striking rod. Sand can be removed in time. And according to the said method, it can avoid damaging the outer peripheral surface of a casting. Further, since the striking rod is swung using the flexible joint, the device configuration for crushing the sand is simplified.

  In particular, even in the case of multiple pieces, if multiple drills and striking rods are arranged so as to correspond to the casting position of each casting product in the sand mold, the sand in each casting product cylinder can be removed simply by moving the entire sand mold. This is advantageous for short-time processing.

  In a preferred aspect of the present invention, the sand mold is a sand mold with a cast frame, and the frame separation is performed after the sand removal step.

  According to this aspect, the sand in the cast product cylinder is removed while the sand mold is supported by the casting frame. Therefore, when the sand in the cast product cylinder is removed by the drill and the striking rod, the entire sand mold is prevented from collapsing, which is advantageous in ensuring work safety and reliable removal of the in-cylinder sand.

  In a preferred aspect of the present invention, the sand removal step is terminated before the temperature of the cast product reaches the A1 transformation point.

  That is, in the case of cast iron, if the cast product is rapidly cooled and the passing speed of the A1 transformation point becomes excessively high, a brittle birch structure tends to be formed. In order to avoid whitening, it is necessary to cool slowly by cooling in the frame. On the other hand, when the cooling rate is slowed down by cooling within the frame, the amount of ferrite precipitated increases, so the strength of the resulting cast product decreases. As a countermeasure, a technique of adding pearlite stabilizing elements such as copper, tin, manganese, etc. has been taken, but the addition of these elements is disadvantageous in terms of cost.

  On the other hand, according to the said aspect, removal of the sand in a casting cylinder is complete | finished before A1 transformation point is reached | attained. By removing the in-cylinder sand, the inner peripheral surface of the cast product is exposed to the atmosphere, so that the passage speed of the A1 transformation point is moderately increased while cooling in the frame. As a result, the cast product tends to have a pearlite structure, which is advantageous for improving the strength. Therefore, it is possible to reduce the amount of pearlite stabilizing element added, and thus it is possible to reduce the amount of pearlite stabilizing added to zero, which is advantageous in terms of cost.

  In a preferred embodiment of the present invention, the cast product is an engine cylinder liner.

  According to the present invention, a sand mold including a cylindrical cast product is positioned below the sand mold drilling device in a state where the axial direction of the cast product is vertical, and is lowered while rotating the drill, whereby the cylinder of the cast product is placed on the sand mold. By drilling a hole through the inside, positioning the sand mold after drilling below the cylinder sand crushing device, inserting a striking rod into the sand mold hole, and swinging the striking rod using the deflection of the flexible joint, Since the sand in the casting cylinder is crushed and removed, the sand in the casting cylinder can be removed in a short time without breaking the sand mold, and the outer peripheral surface of the casting may be damaged. This is advantageous for improving productivity.

  In particular, even in the case of multiple pieces, if a plurality of drills and striking rods are arranged so as to correspond to the casting position of each cast product in the sand mold, the sand in each cast product cylinder can be simply moved. This is advantageous for short-time processing.

The top view of the cylinder liner of the engine as a casting product. The front view made into the partial cross section explaining the process of making a hole in a sand mold. The front view made into the partial cross section explaining the process of removing the sand in a casting product cylinder. The figure which shows typically the cooling curve of a cast iron molten metal.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

  The present embodiment relates to sand removal of the cylinder liner 1 of the engine shown in FIG. 1 as a cylindrical cast product. A large number of ridges 2 extending in the axial direction (longitudinal direction of the cylinder) are formed on the outer peripheral surface of the cylinder liner (hereinafter referred to as “cast product”) 1 at intervals in the circumferential direction. This ridge 2 is for increasing the coupling strength between the cylinder liner and the cylinder block body.

  Cast iron is used for casting of the cast 1, for example, cast iron having a carbon equivalent (CE) of 3.8 to 4.3.

  As shown in FIG. 2, the sand mold 3 including the cast product 1 is placed on a cart 5 as a sand mold conveying device in a state where a cast frame 4 is provided. The sand mold 3 is transported to the drilling station by the carriage 5 and is positioned below the sand mold drilling device 6 that pierces the sand mold 3. The sand mold 3 is supported by the carriage 5 so that the axial direction of the casting 1 is vertical. The sand mold 3 is a multi-piece sand mold, and a plurality of cavities corresponding to the casting 1 are formed at intervals in the vertical and horizontal directions. In FIG. 2, the illustration of the gate, the runway, and the weir is omitted. This illustration is the same in FIG. 3 described later.

  The sand mold punching device 6 includes a plurality of drilling drills 8 for drilling holes 7 passing through the cylinders of the respective castings 1 in the sand mold 3, a drive unit 9 for rotating these drills 8, and lifting and lowering the drill 8 together with the drive unit 9. Elevating unit 10 is provided. Each drill 8 is provided vertically, and is arranged corresponding to the center position of each casting product cavity in the sand mold 3 (the tube center position of the casting product 1).

  As shown in FIG. 3, the sand mold 3 after being drilled by the drill 8 is conveyed to the crushing station while being placed on the carriage 5, and below the in-cylinder sand crushing device 11 that crushes the sand in the cylinder of the cast 1. Positioned on.

  The in-cylinder sand crusher 11 includes an impact rod 14 connected to a rotary shaft 12 by a flexible joint 13 made of a coil spring, a drive unit 15 that rotates the rotary shaft 12, and a flexible joint. 13 and a striking rod 14 are also provided. The rotary shaft 12, the flexible joint 13 and the striking rod 14 are coaxially provided vertically and correspond to the center position of each casting product cavity in the sand mold 3 (cylinder center position of the casting product 1). Are arranged.

  The crushing station is further provided with a sand suction device 17 for sucking and removing the crushed sand. The sand suction device 17 includes a hood 18 that covers the sand mold 3 from above, a suction duct 19, and a pipe 20 that connects the hood 18 and the suction duct 19. The hood 18 has a hole through which the striking rod 14 and the flexible joint 13 are passed. The sand suction device 17 is provided so as to be moved up and down by a lifting unit (not shown).

<Method of removing sand in cylinder of cast product>
After pouring the molten metal into the sand mold 3, the sand mold 3 including the cast product 1 is placed on and supported by the carriage 5 so that the axial direction of the cast product 1 is vertical together with the casting frame 4. As shown in FIG. 4, the sand mold 3 including the cast product 1 is transported by the carriage 5 until the temperature of the cast product 1 reaches an intermediate temperature between the eutectic temperature and the A1 transformation point. Position downward (FIG. 2). The center of the cylinder of each casting 1 is positioned directly below each drill 8.

  In FIG. 4, the symbol “L” means liquid, the symbol “γ” means austenite, the symbol “G” means graphite, and the symbol “α” means ferrite.

  As described above, when the temperature of the casting 1 becomes the intermediate temperature between the eutectic temperature and the A1 transformation point, as shown in FIG. A hole 7 passing through the cylindrical hole is drilled (drilling step).

  Thereafter, the sand mold 3 after drilling is positioned below the in-cylinder sand crushing device 11 of the crushing station by conveyance by the carriage 5. Each hole 7 of the sand mold 3 is positioned directly below each striking rod 14. Next, the sand suction device 17 is lowered to cover the sand mold 3 with the hood 18, and the striking rod 14 is further lowered to be inserted into the hole 7 of the sand mold 3.

  Then, the rotating shaft 12 is rotated. As the rotating shaft 12 rotates, the striking rod 14 is swung by the bending of the flexible joint 13. As a result, the hitting rod 14 hits the hardened sand in the cylinder of the casting 1. As a result, the sand in the cylinder of the cast 1 is crushed. When the rotation of the rotary shaft 12 is started, the sand suction device 17 is operated to suck and remove sand to be crushed by the striking rod 14 (sand removal step).

  The removal of sand in the cylinder of the cast 1 is terminated before the temperature of the cast 1 reaches the A1 transformation point as shown in FIG. Since the inner peripheral surface of the cast product 1 from which the sand has been removed is exposed to the atmosphere, the A1 transformation point passing speed is appropriately increased as shown by the broken line in FIG. The solid line in FIG. 4 is a cooling curve when the sand in the cylinder of the cast 1 is not removed.

  As described above, as a result of the A1 transformation point passing speed of the casting 1 being increased moderately, the casting 1 tends to have a pearlite structure even when the amount of the pearlite stabilizing element is small or zero. In the case where the sand in the cylinder of the cast 1 is not removed (solid line in FIG. 4), if the amount of pearlite stabilizing element is small, a ferrite structure tends to be formed.

  After the sand removal step, when the temperature of the cast product 1 greatly falls below the A1 transformation point, the frame is separated and the cast product 1 is taken out. Thereafter, the sand removal is completed by a vibrating conveyor or a hanger shot blast. Since the frame is broken after the sand in the cylinder is removed, the casting 1 can be shot blasted through a hanger into the opened cylinder hole. Therefore, sand easily falls and damage to the convex portion 2 on the outer peripheral surface of the cast product 1 due to collision between the cast products 1 can be avoided.

  In addition, although the said embodiment is a case where the casting 1 is a cylinder liner of an engine, it cannot be overemphasized that this invention is applicable also to the sand removal of cylindrical castings other than a cylinder liner.

1 Casting product 3 Sand mold 4 Casting frame 5 Carriage (conveying device)
6 Sand type drilling device 7 Hole 8 Drill 9 Drive unit (drive means)
10 Lifting unit (lifting means)
DESCRIPTION OF SYMBOLS 11 Sand type punching device 12 Rotating shaft 13 Flexible joint 14 Rod for impact 15 Drive unit (drive means)
16 Lifting unit (lifting means)

Claims (5)

A method for removing sand in a cylinder from a cylindrical casting cast with a sand mold,
A sand mold containing the cast product is positioned below the sand mold punching device so that the axial direction of the cast product is vertical, a drilling step of drilling holes in the sand mold;
The sand mold after drilling is positioned below the in-cylinder sand crushing device, and comprises a sand removal step of crushing and removing the sand in the cylinder of the cast product,
The sand-type drilling device includes a drill for drilling,
In the drilling step, by lowering the drill while rotating, a hole passing through the cylinder of the cast product is drilled in the sand mold,
The in-cylinder sand crushing device is connected to a rotating shaft provided vertically by a flexible joint, and when the rotating shaft rotates, a rod for striking that is swung by the bending of the flexible joint. Prepared,
In the sand removing step, the rod is inserted into the sand mold hole, and the rotating shaft is rotated and the rod is swung to crush and remove sand in the cylinder of the cast product. Sand removal method inside castings. In claim 1,
The sand mold is a sand mold with a cast frame, and the method of removing sand inside a cylindrical cast product is characterized in that after the sand removal step, frame separation is performed. In claim 1 or claim 2,
A sand removal method inside a cylindrical cast product, wherein the sand removal step is terminated before the temperature of the cast product reaches the A1 transformation point. In any one of Claim 1 thru | or 3,
A method for removing sand from a cylindrical cast product, wherein the cast product is a cylinder liner of an engine. A device for removing sand in a cylinder from a cylindrical casting cast with a sand mold,
A transport device for supporting and transporting the sand mold containing the cast product so that the axial direction of the cast product is vertical;
A drill provided vertically for sand mold drilling, a driving means for rotating the drill, and an elevating means for raising and lowering the drill, and the sand mold including the cast product is positioned below the drill by the conveying device. A sand mold drilling device that lowers the drill while rotating the drill so that a hole passing through the inside of the cylinder of the cast product is drilled in the sand mold,
A striking rod connected to a vertical rotating shaft by a flexible joint and swung by the deflection of the flexible joint when the rotating shaft rotates, and a drive for rotating the rotating shaft And a lifting means for raising and lowering the rotating shaft, and when the sand mold is positioned below the in-cylinder sand crushing apparatus by the conveying device, the rod is lowered and inserted into the hole of the sand mold, An in-cylinder sand crusher that rotates the rotating shaft and swings the rod so that sand in the cylinder of the cast product is crushed.

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