JP2012245561A - Facing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a facing method for more improving and stabilizing the product quality of a vehicular wheel than before.SOLUTION: The facing method includes: a substrate facing step of performing the substrate facing on a side gate opposing area 42 of a rim forming part 41 of an upper mold 40, the side gate opposing area 42 being opposite to a side gate 11; and a main facing step of performing the main facing on the rim forming part 41 and a lower face 44, after the substrate facing step. The method further includes a substrate facing step of performing the substrate facing on a side gate peripheral area 36 of a rim forming part 35 of a horizontal mold 30, followed by a main facing step of performing the main facing on the rim forming part 35 of the horizontal mold 30.

Description

  The present invention relates to a method for coating a mold for casting a vehicle wheel.

  As a casting device for a vehicle wheel or the like, a so-called side gate type low pressure casting device is known (for example, Patent Document 1). The mold used for this low-pressure casting apparatus is configured by combining an upper mold and a lower mold and a pair of horizontal molds that sandwich a set of the upper mold and the lower mold from the side. A pair of horizontal dividing surfaces are provided with runners for sending the molten metal into the mold, and the molten metal is injected into the mold from both sides of the mold through the runner. That is, in the low pressure casting apparatus, the molten metal is filled into the cavity at a low speed, and a product such as a vehicle wheel is cast.

  When casting an aluminum alloy or the like with a low-pressure casting apparatus, a mold is applied in which a coating agent is applied to the surface of the mold (for example, Patent Documents 2 to 3). By this coating mold, the surface of the mold can be protected and the hot water can be improved. Furthermore, a good effect can be obtained for cooling and releasing the casting.

JP-A-8-243720 JP 2000-5842 A JP-A-8-229632

  However, in the conventional coating mold, the quality of the vehicle wheel is not sufficient, and there has been a demand for a coating method capable of producing a higher quality.

  An object of the present invention is to provide a coating method for improving and further stabilizing the quality of a vehicle wheel product.

  The present inventor has found that the above-described problem can be solved by performing coating on a predetermined region of the mold. That is, according to the present invention, the following coating method is provided.

[1] A vehicle wheel in which a cavity for forming a vehicle wheel is formed by an upper mold, a horizontal mold, and a lower mold, and a side gate that opens to a cavity that forms a rim portion of the vehicle wheel is provided. A coating method for a low-pressure casting apparatus, wherein a base coating is performed on a side gate facing region facing the side gate of a rim portion forming portion that forms the rim portion of the vehicle wheel. A base coating step, and then a main coating step in which a main coating is performed on the rim portion forming portion and the lower surface of the upper mold, and a heat insulating coating agent is used for the main coating. A coating method in which a heat-retaining coating agent diluted with the heat-retaining coating agent of the main coating mold is used for the base coating mold.

[2] After removing the coating agent previously applied to the upper-spoke root portion forming portion, in which the spokes of the vehicle wheel form a spoke-root portion connected to the rim portion, the slip-coating die The coating method according to [1], further including a sliding coating step of applying the agent.

[3] A vehicle wheel having a cavity for forming a vehicle wheel formed by an upper mold, a horizontal mold, and a lower mold, and a side gate opening in a cavity forming a rim portion of the vehicle wheel. A low-pressure casting apparatus coating method, wherein a base coating is performed on a side gate peripheral region around the side gate of a rim portion forming portion that forms the rim portion of the vehicle wheel. A coating process, and then a main coating process for performing a main coating process on the horizontal rim portion forming portion. A heat-retaining coating agent is used for the main coating mold, and the base coating process is performed. A mold method in which a heat-retaining coating agent diluted more than the heat-retaining coating agent of the main coating mold is used for the mold.

[4] After the main coating, the coating agent previously applied to the lateral spoke root forming region, in which the spokes of the vehicle wheel form a spoke root connected to the rim, is removed. The coating method according to [3], further comprising a slip coating step of applying a slip coating agent.

[5] The coating method according to [3] or [4], further including a slip coating step of applying a slip coating agent to the lateral side gate peripheral region after the main coating.

[6] The coating method according to any one of [3] to [5], further including a slip coating step of applying a slip coating agent to the lateral runner peripheral area after the main coating.

  By applying the base coating mold to the upper mold side gate facing area and the lateral side gate peripheral area, and performing the main coating mold on the area, etc., the coating film adhesion can be improved and the heat retention can be improved. Directional solidification is improved, and non-rotating and shrinkage defects can be improved. Thereby, the quality of the vehicle wheel can be improved.

It is sectional drawing of the low pressure casting apparatus of the wheel for vehicles. It is a perspective view of the low pressure casting apparatus of a vehicle wheel. It is the figure which looked at the upper model from the side. It is the figure which looked at the low-pressure casting apparatus from the top. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is the perspective view which looked at the horizontal type from the mold division side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

  FIG. 1 is a cross-sectional view of a low-pressure casting apparatus for a vehicle wheel, and FIG. 2 is a perspective view. The low-pressure casting apparatus D is provided with a mold set S for forming a vehicle wheel from a molten metal and a base 10 on which the mold set S is placed.

  The mold set S includes a lower mold 20, a horizontal mold 30, and an upper mold 40. By combining the lower mold 20, the horizontal mold 30, and the upper mold 40, the cavity 50 can be formed inside the mold set S. The horizontal mold 30 refers to a mold that moves in the horizontal direction and forms the cavity 50 while being sandwiched between the upper mold 40 and the lower mold 20. That is, the upper mold 40, the horizontal mold 30, and the lower mold 20 form a cavity 50 for forming a vehicle wheel. The cavity 50 is a cavity having the shape of a vehicle wheel, and is composed of a disk molding part composed of a hub molding part 51 and a spoke molding part 52 and a rim molding part 53. In the mold set S, an insert 21 is attached to the lower mold 20, and the insert 21 can form irregularities in the disk portion of the vehicle wheel.

  After the upper die 40, the horizontal die 30 and the lower die 20 of the low pressure casting apparatus D are coated by the coating method of the present invention, the casting process is performed. Hereinafter, the coating method of the present invention will be described for each mold.

1. Upper mold 1-1. Base coating process / main coating process Before casting, coating is performed on the upper mold 40 of the low-pressure casting apparatus D for the vehicle wheel. The coating method of the upper mold 40 will be described with reference to FIGS. 2 is a perspective view of a low pressure casting apparatus for a vehicle wheel, FIG. 3 is a view of the upper die 40 as viewed from the side, FIG. 4 is a view of the low pressure casting apparatus as viewed from above, and FIG. AA sectional view and FIG. 6 are BB sectional views of FIG.

  The coating method of the low-pressure casting apparatus for a vehicle wheel according to the present invention includes a base coating step of performing base coating on the side gate facing region 42 facing the side gate 11 of the rim portion forming portion 41 of the upper mold 40. Then, a main coating step of performing main coating on the rim portion forming portion 41 and the lower surface 44 of the upper mold 40 is included. Here, the rim portion forming portion 41 is a portion of the upper mold 40 that forms the rim portion of the vehicle wheel, as shown in FIGS. 2 and 3. Further, as shown in FIG. 1, the side gate 11 opens into the cavity 50 (rim forming portion 53). A heat insulating coating agent is used for the main coating mold, and a heat insulating coating agent diluted with respect to the heat insulating coating agent of the main coating mold is used for the base coating mold.

  The heat-retaining coating agent is a coating agent whose main purpose is to improve the heat-retaining property of the mold. As the heat retaining coating agent, a general coating agent for aluminum mold casting can be used. Typical aggregate components of the coating agent include magnesia, alumina, zircon, and titanium oxide. For the base coating mold, a diluted heat retaining coating agent is used rather than the heat retaining coating agent of the main coating mold. A base coating agent dilutes this coating agent 2-3 times. For example, the base coating agent is diluted 9 to 10 times with respect to the stock solution, and the present coating agent is diluted 3 to 5 times with respect to the stock solution. Dilution usually uses general industrial water or tap water. It is preferable to use treated pure water if possible. The base coating mold and the main coating mold are preferably performed at a surface temperature of the mold (upper mold 40) of 200 to 250 ° C. The surface temperature can be adjusted by heating in an atmospheric furnace, directly heating with a burner, or setting a heater in a mold and heating. Moreover, it is more preferable if baking of 350-400 degreeC is implemented after implementing a coating type.

  As shown in FIGS. 2, 3, and 5, the side gate facing region 42 of the upper mold 40 has a width La of 100 to 140 mm facing the side gate 11 of the horizontal mold 30 in the rim portion forming portion 41 of the upper mold 40. This is a substantially rectangular area. The side gate facing region 42 is a portion where the molten metal supplied from the side gate 11 to the cavity 50 (rim forming portion 53) collides, and the side gate facing region 42 is subjected to base coating using a heat insulating coating agent. By this, the coating-film adhesiveness in the main coating type implemented next can be improved. Furthermore, the main coating mold to be implemented next can improve the heat retaining property of the mold and prevent a rapid temperature drop of the molten metal. As a result, the directional solidification can be improved and the hot water circulation can be improved.

  After the base coating mold for applying the heat insulating coating agent to the side gate facing region 42, the main coating mold for applying the heat insulating coating agent to the rim portion forming portion 41 and the lower surface 44 of the upper mold 40 is applied. Do. In addition, the side gate opposing area | region 42 is included in the rim | limb part formation part 41 which apply | coats a heat retention coating agent in this coating process. That is, since the base coat type heat retaining coating agent and the main coating type heat retaining coating agent are applied to the side gate facing region 42, the film thickness becomes thicker and stronger, and the heat retaining property is further improved. By improving the heat retaining property of the side gate facing region 42, the molten metal around the side gate is finally solidified to improve the hot water circulation and improve the quality of the product.

1-2. Sliding coating step It is preferable to have a sliding coating step of applying the sliding coating agent after removing the coating agent previously applied to the spoke root forming portion 43 of the upper mold 40. As shown in FIGS. 2 and 3, the spoke root portion forming portion 43 is a portion where the spoke of the vehicle wheel forms a spoke root portion that connects to the rim portion, and particularly the rim portion forming portion 41 of the upper mold 40. It is a part protrudingly formed on the lower side. By removing the coating agent on the outer peripheral surface that becomes the spoke root formation portion 43, the effect of improving the heat retaining property of the mold is lost, and the cooling of the spoke root that is a thick portion of the vehicle wheel and is likely to be solidified finally is improved. And the occurrence of sink defects at this site can be suppressed. When the coating agent is removed, the molten metal reacts with the mold and tends to cause galling when demolding. For this reason, it is preferable to apply a slip coating agent that prevents reaction with the molten metal without improving the heat retention of the mold. By applying the slip coating agent, the slipping property at the time of demolding can be improved, the galling can be prevented, the product quality can be improved and the upper mold 40 can be prevented from being worn.

  The slip coating agent is a coating agent that improves the sliding property between the casting material and the mold and can prevent galling. Sliding coating agents are mainly emulsion (emulsification) (oil / silicone / wax is the main component), water-based graphite, BN (boron nitride) (mainly graphite), water-based heat resistant pigment (mainly stone, mica) Component). Specific examples include a mixed coating agent of graphite-based coating agent and boron nitride.

  As described above, the base coating and the main coating are performed on the upper mold 40, and the directional solidification is achieved by removing the coating agent and performing the sliding coating on the thick portion of the wheel. Improved and quality is improved. Compared to the main coating type alone, the base coating type improves the heat insulation of the mold to improve the hot water supply and stabilizes the coating for a longer time, thereby improving and stabilizing the product quality. be able to. Further, the slip coating mold can prevent the casting material and the mold from being galled and can prevent the mold from being worn.

2. Horizontal type 2-1. Base coating process / main coating process Before casting, the horizontal mold 30 of the low-pressure casting apparatus D for vehicle wheels is coated. The coating method of the horizontal mold 30 will be described with reference to FIGS. 2 and 4 to 7. FIG. 7 is a perspective view of the horizontal mold 30 as viewed from the mold division side.

  The vehicle wheel low pressure casting apparatus coating method according to the present invention includes a base coating step of performing base coating on the side gate peripheral region 36 around the side gate 11 of the rim portion forming portion 35 of the horizontal mold 30; Next, the rim portion forming portion 35 of the horizontal mold 30 includes a main coating process for performing the main coating mold. Here, the rim portion forming portion 35 is a portion that forms the rim portion of the vehicle wheel of the horizontal mold 30, as shown in FIG. A heat insulating coating agent is used for the main coating mold, and a heat insulating coating agent diluted with respect to the heat insulating coating agent of the main coating mold is used for the base coating mold.

  As shown in FIGS. 2 and 7, the side gate peripheral region 36 of the horizontal mold 30 refers to a region in the rim portion forming portion 35 where the lateral width Lb of the side gate 11 is 50 to 70 mm.

  As the heat insulating coating agent, the same heat insulating coating agent used for the upper mold 40 can be used. As with the upper mold 40, the base coat type heat insulating coating agent is preferably a diluted coating agent rather than the main coating type heat insulating coating agent. A base coating agent dilutes this coating agent 2-3 times. For example, the base coating agent is diluted 9 to 10 times with respect to the stock solution, and the present coating agent is diluted 3 to 5 times with respect to the stock solution. The base coating mold and the main coating mold are preferably performed at a surface temperature of the mold (horizontal mold 30) of 200 to 250 ° C.

2-2. Sliding coating step After the main coating, it is preferable to have a sliding coating step of applying the sliding coating agent after removing the coating agent previously applied to the spoke root portion forming region 38 of the horizontal mold 30. . As shown in FIGS. 2, 4, 6, and 7, the spoke-shaped root portion forming region 38 of the horizontal mold 30 is a region that forms a spoke root portion that connects the spokes of the vehicle wheel to the rim portion. By removing the coating agent in the spoke root portion forming region 38 of the horizontal mold 30, the cooling performance of the spoke root portion, which is a thick portion of the vehicle wheel, is improved, and the sink defect in this portion is improved by improving the hot water circulation. Can be suppressed. Further, by applying a slip coating agent, it is possible to prevent galling and improve the slipping property when demolding. Thereby, abrasion of the horizontal mold | type 30 can also be prevented.

  As the slip coating agent, the same slip coating agent used for the upper mold 40 can be used.

2-3. Sliding coating step It is preferable to have a sliding coating step of applying a sliding coating agent to the side gate peripheral region 36 of the horizontal mold 30 after the main coating. Further, it is preferable to have a slip coating step of applying a slip coating agent to the runner peripheral region 37 of the dividing surface 34 of the horizontal mold 30 after the main coating mold. The runner peripheral region 37 refers to a region having a width of 20 to 30 mm in the vicinity of the runner 31 of the dividing surface 34. By performing the slip coating mold, it is possible to prevent galling between the casting material and the mold, and to improve the slipping property when removing the cast product. Thereby, abrasion of the horizontal mold | type 30 can also be prevented.

  A slip coating agent is a coating agent that improves slipperiness and prevents galling. Sliding coating agents are mainly emulsion (emulsification) (oil / silicone / wax is the main component), water-based graphite, BN (boron nitride) (mainly graphite), and water-resistant heat-resistant pigment (mainly stone, mica). Component). Brush coating is preferable for the slip coating type in which the slip coating agent is applied to the side gate peripheral region 36 and the runner peripheral region 37.

3. Lower mold 3-1. Main coating process Before casting, the lower mold 20 of the low-pressure casting apparatus D for vehicle wheels is coated. As shown in FIG. 2, it is preferable to apply a heat retaining coating agent to the entire upper surface 23 of the lower mold 20 and the stalk presser plate 24. As the heat retaining coating agent, the same one applied to the upper mold 40 and the horizontal mold 30 can be used. This coating mold is preferably performed at a surface temperature of the mold (lower mold 20) of 200 to 250 ° C.

  Next, the manufacturing method of the vehicle wheel using this low pressure casting apparatus D is demonstrated. The upper mold 40, the horizontal mold 30, and the lower mold 20 are closed to form a cavity 50 for forming a vehicle wheel (see FIGS. 1 and 2). Then, a pressurized gas such as air or inert gas is fed into the molten metal holding furnace 60. The supplied pressurized gas pushes up the molten metal M in the molten metal holding furnace 60 and supplies the molten metal M from the stalk 70 and the runner 31 into the cavity 50.

  After the molten metal has solidified in the cavity 50 and the runner 31, the pair of horizontal molds 30 are removed (open in the direction perpendicular to the paper surface of FIG. 1). At this time, the L-shaped runner (the molten metal solidified) formed by the runner 31 of the horizontal mold 30 is also released from the horizontal mold 30. Thereafter, the upper mold operating tool 80 is operated to lift the upper mold 40 and the push plate 90 together with the cast vehicle wheel, and the lower mold 20 fastened and fixed to the base 10 is removed. In this state, the vehicle wheel cast from the upper mold 40 is demolded by pressing the rim flange by holding the extrusion plate 90 and raising the upper mold 40.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

1. Upper mold 1-1. Base coating process / main coating process Before casting, coating was performed on the upper mold 40 of the low-pressure casting apparatus D for a vehicle wheel. First, a base coating mold was applied to the side gate facing region 42 (width La of 100 to 140 mm) of the upper mold 40. At this time, the surface temperature of the upper mold 40 was set to 200 to 250 ° C. The base coating type heat-retaining coating agent was diluted 10 times with pure water and used.

  Next, the main coating mold was applied to the rim portion forming portion 41 and the lower surface 44 of the upper mold 40. At this time, the surface temperature of the upper mold 40 was set to 200 to 250 ° C. A base coating type heat-retaining coating agent was diluted 3 times with pure water.

1-2. Sliding coating process The coating agent previously applied to the spoke root forming part 43 of the upper mold 40 was removed with a grindstone. Next, slip coating was performed. As the slip coating agent, a mixed coating agent obtained by mixing a graphite-based coating agent and boron nitride in a ratio of 1: 1 was used.

2. Horizontal type 2-1. Base Coating Process / Main Coating Process The base coating mold was applied to the side gate peripheral region 36 of the horizontal mold 30. At this time, the surface temperature of the horizontal mold 30 was set to 200 to 250 ° C. The base coating type heat-retaining coating agent was diluted 10 times with pure water and used.

  Next, the main coating mold was applied to the rim portion forming portion 35 of the horizontal mold 30. At this time, the surface temperature of the horizontal mold 30 was set to 200 to 250 ° C. The heat-retaining coating agent of this coating mold was diluted 3 times with pure water and used.

2-2. Sliding coating process The coating agent previously applied to the spoke root formation region 38 of the horizontal mold 30 was removed with a grindstone. Next, slip coating was performed. As the slip coating agent, a mixed coating agent in which a graphite coating agent and boron nitride were mixed at a ratio of 1: 1 was used.

2-3. Sliding coating process After the main coating, the sliding coating was performed on the side gate peripheral region 36 (width 50 to 70 mm) of the horizontal mold 30. In addition, after the main coating mold, a slip coating mold was applied to the runner peripheral area 37 (width 20 to 30 mm) of the horizontal mold 30. As a sliding mold agent, boron nitride and kerosene were mixed 1: 2 and diluted and brush-coated.

3. Lower mold 3-1. Main coating process A heat-retaining coating agent was applied to the entire upper surface 23 of the lower mold 20 and the stalk presser plate 24 to perform the main coating. At this time, the surface temperature of the lower mold 20 was set to 200 to 250 ° C. The coating was applied by diluting a heat-retaining coating agent and pure water 1: 3.

  By the above coating mold, the internal quality of the vehicle wheel, especially the sink mark defect, could be improved as compared with the conventional one.

  The present invention can be used as a low pressure casting apparatus for a vehicle wheel.

10: base, 11: side gate, 20: lower mold, 21: insert, 23: upper surface of (lower mold), 24: stalk presser plate, 30: horizontal mold, 31: runner, 34: divided surface, 35 : (Horizontal) rim portion forming portion, 36: side gate peripheral region (of horizontal rim portion forming portion), 37: (horizontal) runner peripheral region, 38: (horizontal) spoke root forming region, 40 : Upper mold, 41: (upper mold) rim portion forming portion, 42: side gate facing region (of upper rim portion forming portion), 43: (upper mold) spoke root forming portion, 44: (upper Bottom surface of mold, 50: cavity, 51: hub molding part, 52: spoke molding part, 53: rim molding part, 60: molten metal holding furnace, 70: molten metal supply pipe, 80: upper mold operating tool, 90: Press plate, D: low pressure casting apparatus, M: molten metal, S: mold set.

Claims (6)

A vehicle wheel low-pressure casting apparatus in which a cavity for forming a vehicle wheel is formed by an upper mold, a horizontal mold, and a lower mold, and a side gate that opens to a cavity that forms a rim portion of the vehicle wheel is provided. The coating method of
A base coating step of performing base coating on a side gate facing region facing the side gate of a rim portion forming portion of the upper mold that forms the rim portion of the vehicle wheel;
Then, a main coating step of performing main coating on the rim portion forming portion and the lower surface of the upper mold,
A heat-retaining coating agent is used for the main coating mold,
A coating method in which a heat-retaining coating agent diluted more than the heat-retaining coating agent of the main coating mold is used for the base coating mold.   The spokes of the vehicle wheel form a spoke root to be connected to the rim, and after removing the coating agent previously applied to the upper root portion of the spoke root, a slip coating agent is applied. The coating method according to claim 1, further comprising a sliding coating step. A vehicle wheel low-pressure casting apparatus in which a cavity for forming a vehicle wheel is formed by an upper mold, a horizontal mold, and a lower mold, and a side gate that opens to a cavity that forms a rim portion of the vehicle wheel is provided. The coating method of
A base coating step of performing base coating on a side gate peripheral region around the side gate of the lateral type, the rim portion forming portion forming the rim portion of the vehicle wheel;
Next, a main coating step of performing a main coating on the horizontal rim forming portion,
A heat-retaining coating agent is used for the main coating mold,
A coating method in which a heat-retaining coating agent diluted more than the heat-retaining coating agent of the main coating mold is used for the base coating mold.   After the main coating, after removing the coating agent previously applied to the horizontal-type spoke root forming region, the spokes of the vehicle wheel form a spoke root to be connected to the rim, and then slip. The coating method according to claim 3, further comprising a sliding coating step of applying a coating agent.   5. The coating method according to claim 3, further comprising a slip coating step of applying a slip coating agent to the peripheral region of the side gate after the main coating.   The coating method according to any one of claims 3 to 5, further comprising a slip coating step of applying a slip coating agent to the lateral runner peripheral region after the main coating.

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