JP2014076450A - Gravity casting apparatus and gravity casting method for knuckle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravity casting apparatus capable of manufacturing a knuckle having excellent quality and a gravity casting method using the apparatus.SOLUTION: A gravity casting apparatus 1 for a knuckle has a metal-mold 2 comprising a first runner 6 extending from a gate 5 in vertical direction, a second runner 7 which is communicated with the first runner 6 and extends in a horizontal direction, and a cavity 9 communicating with the second runner 7 through a dam 8. A columnar salient 4A for forming a bottomed hole in a bearing support part for the knuckle is provided in the cavity 9. The cavity 9 has a pressurizing boss part 9A on the axis of the columnar salient 4A. Further, the apparatus has a blockage component 13 for blocking the second runner 7, and a pressurizing pin 18 for pressurizing molten metal in the pressuring boss part 9A.

Description

  The present invention relates to a gravity casting apparatus for a knuckle for manufacturing a knuckle for an automobile, which is a part for connecting a bearing supporting a wheel and a suspension, and a gravity casting method using the apparatus.

  A gravity casting apparatus for manufacturing a knuckle by a gravity casting method is known as disclosed in Patent Document 1 below. In the gravity casting apparatus of Patent Document 1, a riser portion is provided above a portion corresponding to a bearing support portion of a cavity, and a piston is entered from a sprue provided above the cavity and the riser portion to press the molten metal in the riser portion. It prevents the occurrence of casting defects such as sinkholes.

  However, if the molten metal is poured from the spout above the cavity, the molten metal entrains much of the oxide generated by the turbulent flow, so even if the molten metal is pressurized by the piston, casting defects caused by the oxide can be prevented. Therefore, there is a problem that a knuckle excellent in quality cannot be manufactured.

JP 2006-51507 A

  Therefore, the present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a knuckle gravity casting apparatus capable of producing a knuckle excellent in quality and a gravity casting method using the apparatus.

  The present invention has been made to solve the above problems, and a gravity casting apparatus for a knuckle according to the present invention includes a first runner 6 extending vertically downward from a gate 5 and a communication with the first runner 6. A knuckle gravity casting apparatus 1 having a mold 2 provided with a second runner 7 that extends in the horizontal direction and a cavity 9 that communicates with the second runner 7 via a weir 8. 9 is provided with a cylindrical convex portion 4A for forming a bottomed hole in the bearing support portion of the knuckle, and the cavity 9 has a pressing boss portion 9A on the axis of the cylindrical convex portion 4A. And having a blocking member 13 for blocking the second runner 7 and a pressure pin 18 for pressing the molten metal of the pressurizing boss portion 9A.

  The gravity casting method according to the present invention is characterized in that gravity casting is performed using the knuckle gravity casting apparatus 1 having the above-described configuration.

  ADVANTAGE OF THE INVENTION According to this invention, the casting defect by the entrainment of an oxide, a shrinkage nest, etc. can be prevented, and the knuckle excellent in quality can be manufactured.

It is sectional drawing of the gravity casting apparatus for knuckles of this embodiment. It is a figure which shows the state after a molten metal is poured. It is a figure which shows the state which the interruption | blocking member interrupted | blocked the 2nd runner. It is a figure which shows the state which pressurized the molten metal with the pressurization pin.

  A knuckle gravity casting apparatus according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the knuckle gravity casting apparatus 1 includes a mold 2 including an upper mold 3 and a lower mold 4. The upper mold 3 is formed with a gate 5 for pouring molten metal by a ladle (not shown). The gate 5 is defined by the upper mold 3 and the lower mold 4 and communicates with the first runner 6 that extends vertically downward. The lower end portion of the first runner 6 is defined by the upper mold 3 and the lower mold 4 and communicates with the second runner 7 that extends in the horizontal direction (left-right direction in FIG. 1). The upper mold 3 and the lower mold 4 define a weir 8 and a cavity 9, and the second runner 7 communicates with the cavity 9 via the weir 8 located at the lower end of the cavity 9. Accordingly, the molten metal poured from the gate 5 is supplied to the cavity 9 via the first runner 6, the second runner 7 and the weir 8.

  The upper mold 3 is connected to a movable plate (not shown). When the movable plate is moved upward in FIG. 1 by a driving means (not shown), the upper mold 3 is separated from the lower mold 4. It is configured. Further, when the movable plate is moved downward from FIG. 1 by the driving means from the separated position, the upper die 3 is in a state of contacting the lower die 4 (the state shown in FIG. 1). Yes.

  A hydraulic cylinder 10 as a blocking member driving means is fixed to the lower surface 4a of the lower mold 4. The cylinder rod 11 of the hydraulic cylinder 10 is connected to the blocking member 13 by a coupling 12 in a hole 4 b formed in the lower mold 4. When the hydraulic cylinder 10 is driven, the tip of the blocking member 13 is configured to enter the second runner 7. The second runner 7 is shut off when the tip of the blocking member 13 abuts or approaches a portion of the upper mold 3 that defines the second runner 7.

  A hydraulic cylinder 14 as a pressure pin driving means is fixed to the upper surface 3 a of the upper mold 3 by a support bar 17. The cylinder rod 15 of the hydraulic cylinder 14 is connected to a pressure pin 18 through a coupling. A lower end portion of the pressure pin 18 is disposed in a hole 3 b formed in the upper mold 3. When the hydraulic cylinder 14 is driven, the tip of the pressurizing pin 18 enters a pressurizing boss portion 9A described later, and the pressurizing pin 14 pressurizes the molten metal M in the pressurizing boss portion 9A. Yes.

  In order to form a bottomed hole in a bearing support portion of a knuckle that is a cast product, the lower mold 4 includes a columnar convex portion 4A that protrudes upward in FIG. The axis of the cylindrical convex portion 4A and the axis of the pressure pin 18 described above substantially coincide. The columnar convex portion 4A is disposed in the cavity 9, and forms a bottomed hole in the bearing support portion of the knuckle. The cavity 9 is provided with a processing boss portion 9A defined by the upper mold 3 on the axis of the cylindrical convex portion 4A and at the upper end of the cavity 9. Since the portion cast by the pressurizing boss portion 9A is surplus, it is cut from the product portion after casting, and the above-mentioned bottomed hole is processed into a through hole.

  The mold 2 is provided with an unillustrated extrusion pin. After the upper mold 3 is separated from the lower mold 4, the molten metal M solidified by the extrusion pin can be extruded and taken out from the mold 2. Yes.

  Next, a gravity casting method using the knuckle gravity casting apparatus 1 will be described. In the gravity casting method, first, a molten metal preparation step for storing molten metal M in a ladle (not shown) is performed to obtain the state shown in FIG.

  Next, a pouring process of pouring the molten metal in the ladle through the gate 5 is performed. The molten metal M poured from the gate 5 flows through the first runner 6 due to gravity to the lower end of the first runner 6, changes the flow in the horizontal direction by the second runner 7, and passes through the weir 8. It flows into the lower end of the cavity 9. The molten metal M fills the cavity 9 so as to be pushed upward, and finally fills the inside of the pressurizing boss portion 9A. Since the pouring step is performed in this manner, the molten metal is difficult to entrain oxide during pouring, and it is possible to prevent casting defects caused by the oxide from occurring in the knuckle.

  After the pouring process is completed and the cavity 9 is filled with the molten metal M as shown in FIG. 2, the hydraulic cylinder 10 is driven to cause the blocking member 13 to enter the second runner 7. A runner blocking process is performed in which the tip is brought into contact with or close to the upper mold 3 to block the second runner 7 (see FIG. 3).

  Thereafter, a pressurizing step is performed in which the hydraulic cylinder 14 is driven to cause the pressurizing pin 18 to enter the pressurizing boss portion 9A of the cavity 9 (see FIG. 4). By performing the pressurizing step after performing the runner shut-off process for shutting off the second runner 7 with the shut-off member 13, the pressure is applied to the molten metal M without releasing the pressure to the first runner 6 and the second runner 7. Can affect. Therefore, the adhesion of the molten metal M is also improved at the end of the cavity 9 (the end of the knuckle arm, etc.). Moreover, the molten metal M for solidification shrinkage can be replenished under pressure, and casting defects such as sinkholes can be prevented in the knuckle as a cast product.

  When the molten metal M in the cavity 9 is solidified by the mold cooling means (not shown), the hydraulic cylinder 10 is driven to retract the blocking member 13 from the second runner 7, and then the upper mold 3 is separated from the lower mold 4. A mold opening process is performed. In the mold opening process, the upper mold 3 is separated from the lower mold 4 by moving a movable plate (not shown) by a driving means (not shown). Then, after the hydraulic cylinder 14 is driven and the pressure pin 18 is retracted, a casting product taking-out step of taking out a knuckle as a casting product with an unillustrated extrusion pin provided in the mold 2, and release into the cavity 9. A release agent application process for applying the agent and a mold clamping process for bringing the upper mold 3 into contact with the lower mold 4 are sequentially performed. The above is the gravity casting method.

  The gravity casting apparatus and gravity casting method for a knuckle according to the present invention are not limited to the above-described embodiments, and various modifications and improvements can be made within the scope described in the claims. For example, in the above-described embodiment, the pressure pin 18 is disposed on the upper mold 3 side, but may be configured to be disposed on the lower mold 4 side.

  In the above-described embodiment, the blocking member 13 is disposed on the lower mold 3 side, but may be configured to be disposed on the upper mold 4 side.

1 Gravity casting equipment for knuckles 2 Mold 3 Upper mold
DESCRIPTION OF SYMBOLS 4 Lower mold | type 4A Columnar convex part 4a Lower surface 4b Hole 5 Spout 6 1st runner 7 2nd runner 8 Weir 9 Cavity 9A Pressurizing boss part 10 Hydraulic cylinder 11 Cylinder rod 12 Coupling 13 Shut off member 14 Hydraulic cylinder 15 Cylinder rod 16 Coupling 17 Support rod 18 Pressure pin M Molten metal

Claims (2)

A mold comprising a first runner that extends vertically downward from the gate, a second runner that communicates with the first runner and extends in the horizontal direction, and a cavity that communicates with the second runner via a weir. Gravity casting apparatus for knuckles having
A cylindrical convex portion for forming a bottomed hole in the bearing support portion of the knuckle is disposed in the cavity,
The cavity has a pressing boss on the axis of the cylindrical convex portion,
A blocking member for blocking the second runner;
A gravity casting apparatus for a knuckle, comprising a pressure pin for pressurizing the molten metal of the pressure boss.   Gravity casting using the gravity casting apparatus for knuckles according to claim 1.

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