Casting device, method for using the device, casting device of vehicle wheel, method for using the device, and vehicle wheel

Abstract: A casting mold has a main body provided with a vent hole opened up in a casting space of said main body. The im­ provement is characterized in that the vent hole is provided with air discharging means and air feeding means which are disposed at the vent hole and the air discharging means and air feeding means are suitable selected so that air within the casting space can be discharged and a pressurized air can be fed toward the casting space through the vent hole.

Description: This invention relates to a casting device having a mold provided with a main body and a casting space, and to a method for using the device. [Brief Description of the Prior Art] In a conventional casting device, when a casting is going to be manufactured, a mold temperature is set sufficiently high in order to obtain a favorable run of a hot melt. This conventional casting device, however, has such disadvantages as that as the mold temperature is set sufficiently high, it takes a long time for the hot melt to be hardened, and as a result, the casting structure of the casting does not become dense, and therefore, a high strength is difficult to obtain. Also, in a conventional low pressure casting device of a vehicle wheel, a main body of a mold is provided at its lower part with a weir and a hot melt is poured into a casting space through this weir (Japanese Patent Early Laid-open Publication No. Sho 55-120465). However, this conventional casting device has such disadvantages as that as the cooling device is disposed at a lower part of the main body of the mold, it is difficult to maintain the hot melt in a constant level of temperature, and as a result, a casting defect tends to occur. Also, notwithstanding that a high strength is required for a disk portion of a vehicle wheel, as the weir is disposed as the lower part of the main body of the mold in the conventional casting device, it is difficult to cool the disk portion, and as a result, the disk portion is difficult to be improved in strength. The present invention has been accomplished in order to overcome the above-mentioned disadvantages of the prior art. SUMMARY OF THE INVENTION It is therefore the object of the present invention to provide a casting device, and a method for using the device, with which a favorable run of a hot melt is maintained without raising the mold temperature, and a casting structure of high density and of high strength can be obtained. This object is achieved by a vent hole opening into the casting space and being provided with air discharging means for discharging air from the casting space and further being provided with feeding means for feeding the casting space with presurized air through the vent hole. The device may be provided with an auxiliary space arranged at the upper part of the casting space and communicating with the casting space. An inlet hole can be provided for introducing presurized air into the auxiliary space. On a portion of a wall of the casting space might be provided with a marking means for casting a mark on the casting structure and between the auxiliary space and the casting space may be disposed a border surface in the vicinity of the marking means. With this arrangement it is possible to print clear casting marks, even if the casting mark is tiny. The object of the invention can also be achieved by a method for using the casting device. The method consists in pouring a hot melt into the casting space of the mold and flowing pressurized air into the vent hole after the hot melt reaches the vent hole which communicates with the casting space. The casting device and the method for using the device according to the invention can be used for casting vehicle wheels. The casting space is used for molding the disk of the wheel. The invention will become apparent to those skilled in the art after consideration of the following preferred embodiments of the invention which are provided by way of example and do not limit the invention. Brief description of the drawings Fig. 1 is a partial sectional view of a casting device, Fig. 2 is an enlarged sectional view of a portion indicated by II of Fig. 1, Fig. 3 is a sectional view taken on the line III-III of fig. 2, Fig. 4 is a sectional view of a second embodiment for casting a wheel cup and Fig. 5 is a perspective view of a wheel cup casted with the mold of fig. 4. DETAILED DESCRIPTION OF THE EMBODIMENTS One preferred embodiment of a casting device according to the present invention will be described with reference to the drawings. In Fig. 1, M denotes a mold for molding a vehicle wheel. The mold 1 comprises a combination of a lower mold 1, a horizontal mold 2 and an upper mold 3. This mold M has a casting space 4 having the shape of a vehicle wheel. 11 denotes a first nest of the lower mold 1 and is secured to a central portion of the lower mold 1 by a bolt 12. With this first nest 11 an outer surface of a hub portion (of the vehicle wheel) is shaped. A second nest 111 of the lower mold 1 is secured to the outer surface of the first nest 11 also by the bolt 12. This nest 111 is for shaping an axle hole of the vehicle wheel. Nest 31 of the upper mold 3 is engaged with a central portion of the upper mold 3. This nest 31 shapes a rear surface of the hub portion of the vehicle wheel. 41 denotes a feeding head space, 42 denotes a hot melt passage communicated with the casting space 4, and 43 denotes a gate formed at the hot melt passage 42. Next, the nest 31 portion in the upper mold 3 will be described in detail with reference to Figs. 2 and 3. The nest 31 of the upper mold 3 is open at its upper end, with which a vent barrel 5 is engaged. 6 denotes an extruding pin which is reciprocally movably inserted through the central portion of the vent barrel 5. A partition wall 51 is integrated in the vent barrel 5. Underneath of the partition wall 51 of the vent barrel 5 is a vent room or auxiliary space 7. 54 denotes a contact surface between the vent barrel 5 and the nest 31 of the upper mold 3 enclosing a small gap as a communicating passage of this invention. Through this communicating passage at the contact surface 54, the casting space 4 and the auxiliary space 7 are communicated with atmosphere. 511 designates vent holes formed in the partition wall 51. Next, 52 denotes a lid member which covers the opening at the upper end of the vent barrel 5. The lid member 52 is formed with a pressurized air inlet hole 53. 8 denotes a connecting piece engaged with the inlet hole 53. 81 denotes a gas pipe connected with the connecting piece 8. By virtue of the foregoing arrangement, when a shutter or feeding valve 82 of the gas pipe 81 is opened, the pressurized air can enter into the vent barrel 5 and thus into the auxiliary space 7 through the connecting piece 8. A method for using such constructed casting mold M will be described next. First, in the state where the feeding valve 82 for pressurized gas is closed and a discharging valve 83 is opened, a hot melt is poured into the casting space 4. At this time, air within the casting space 4 is discharged through the discharge valve 83. And, when the hot melt reached a lower end portion of the auxiliary space 7 (see the imaginary line A of Fig. 2), the discharging valve 83 is closed and the feeding valve 82 for pressurized gas is opened to feed the pressurized gas into the auxiliary space 7 to raise the internal pressure of the auxiliary space 7. Then, the surface of the hot melt now reaching the lower end portion of the auxiliary space 7 is pressurized. As a result, the hot melt can easily enter into every corner of the casting space 4. The hot melt moves upward within the casting space 4. At this time, air within the casting space 4 is discharged into atmosphere through the communication passage at the contact surface 54. And, when the hot melt reaches the border line A between the casting space 4 and the auxiliary space 7, the gap or communication passage of the contact surface 54 is blocked with the hot melt. Therefore, air within the auxiliary space 7 can not discharge. As a result, the temperature of the hot melt will not raise. Therefore, the interior of the auxiliary space 7 is secured as a pressur space. And, the feeding valve 82 of the gas pipe 81 is opened to feed the pressurized air into the auxiliary space 7 to raise the internal pressure of the auxiliary space 7. Then, the surface A of the hot melt now reaching the lower end portion of the auxiliary space 7 is pressurized. As a result, the hot melt enters easily into every corner of the auxiliary space 7. As the casting device of claim 1 is constructed as mentioned above, gas within the casting space can be discharged and a pressurized fluid can be fed in the direction of the casting space through the vent hole. Accordingly, in the case that this casting device is used, a favorable run of a hot melt can be maintained without raising the temperature of the mold. Therefore, there can be obtained a casting structure of high density and a casting of high strength. According to the method for using the casting device as described above, the surface of the hot melt within the casting space can be pressurized through the vent hole after the hot melt is poured. Accordingly, a favorable run of a hot melt can be enhanced. Therefore, in the case that the method for using the casting device is carried out, a favorable run of a hot melt can be maintained without raising the temperature of the mold. Therefore, there can be obtained a casting of a high density of casting structure, i.e., a casting of high strength. The casting device may be used for casting a vehicle wheel. Gas within the casting space 4 for forming the disk of the wheel can be discharged and a pressurized fluid can be fed in the direction of the disk forming casting space through the vent hole 511. Further, the surface of the hot melt within the casting space for the disk can be pressurized through the vent hole after the hot melt is poured. Accordingly, a favorable run of a hot melt can be enhanced. Therefore, in using the method described for casting vehicle wheels a favorable run of a hot melt can be maintained without raising the temperature of the mold. Therefore, there can be obtained a vehicle wheel of high density casting structure, and of high strength. The A communicating passage disposed on the border line A between the casting space 4 and the auxiliary space 7 in the mold so that the auxiliary space is communicated with atmosphere through this communicating passage. When a hot melt is poured into the casting space, the hot melt moves upward along the wall surface of the casting space 4, however, when the hot melt reaches the border line A between the casting space 4 and the auxiliary space 7, the air within the auxiliary space can not discharge anymore, and therefore, the hot melt does not further move upward and thus, the auxiliary space 7 will act as a pressurized space. Accordingly, in the case that this casting device is used, a favorable run of a hot melt can be maintained without raising the temperature of the mold. Therefore, there can be obtained a casting of high density casting structure and of high strength. In Fig. 4, M denotes a mold for molding a wheel cap C which comprises a combination of a lower mold 1 and an upper mold 3. This mold M has a wheel cap-shaped molding space 4. A hot melt port 422 and a hot melt passage 42 are formed in the upper mold 3 on a border surface between the upper mold 3 and the lower mold 1. This hot melt passage 42 is continuous to the hot melt port 422 and opens into the casting space 4. A marking means 412 for casting a mark on the wheel is formed on an upper wall surface of the casting space 4. This casting mark means 412 is designed as such that a mark of "ABC" is printed out on the surface of the wheel cap C (Fig. 5). In the upper mold 3 is provided an auxiliary space 55 opened in the vicinity of the casting mark means 412 into the casting space 4. That is, the border surface between the auxiliary space 55 and the casting space 4 is positioned in the vicinity of the mark means 412. An air vent or vent holes 512 are mounted on an opening end of the auxiliary space 55. This air vent 512 is adapted to prevent the hot melt from entering into the auxiliary space 55. 53 denotes an inlet hole for pressurized fluid formed in the upper mold 3. This inlet hole 53 is communicated with an upper end portion of the auxiliary space 55. 8 denotes a connecting pipe inserted in the inlet hole 53. Through this connecting pipe 8, the inlet hole 53 and the gas pipe 81 are connected with each other. Next, the operation of such constructed marking means will be described. First, a hot melt is poured into the casting space 4 through the hot melt port 422 and the hot melt passage 42. After filling the casting space 4 with hot melt a pressurized gas is fed into the auxiliary space 55 through the inlet hole 53 to raise the internal pressure of the auxiliary space 51. Then, the surface S of the hot melt which now reaches the lower end portion of the auxiliary space 55 is pressurized. As a result the hot melt in the vicinity of the auxiliary space 55 is strongly pressed against the wall surface of the casting space 4, the hot melt is also strongly pressed against the casting mark means 412. As a result, a casting mark is clearly formed thereon. As the marking means is such constructed as mentioned above, when a pressurized gas is introduced into the auxiliary space after the hot melt is poured into the casting space, the internal pressure of the auxiliary space pressurizes the surface of the hot melt (the border surface with respect to the auxiliary space). As a result, as the hot melt in the vicinity of the auxiliary space is strongly pressed against the wall surface of the casting space, the hot melt is also strongly pushed against the mark forming portion. Therefore, if this marking means is used, even a tiny mark, for example, can clearly be printed out.

Claims: Casting device having a mold (M) provided with a main body (1,2,3) and a casting space (4),characterized in that a vent hole (511) opens into said casting space (4), the vent hole (511) being provided with air discharging means for discharging air from the casting space and with feeding means (81,82) for feeding said casting space with pressurized air through the vent hole (511). Device according to claim 1, wherein at the upper part of the casting space (4) is arranged an auxiliary space (7,55) which communicates with the casting space, the mold is further provided with an inlet hole (53) for introducing pressurized air into the auxiliary space. Device according to claim 2, wherein the device further including marking means (412) for casting a mark, said marking means being arranged on a portion of a wall of the casting space (4) in the mold (M), further a border surface is provided between the auxiliary space (55) and the casting space (4) in the vicinity of the wall portion having the marking means. Method for using a casting device having a mold (M) with a casting space (4) and a vent hole (511,512) communicating with the casting space according to claim 1, characterized in pouring a hot melt into the casting space (4) of the mold (M) and flowing pressurized air into the vent hole (511,512) after the hot melt reaches the vent hole. Use of a casting device and method as claimed in claims 1 to 4 for producing vehicle wheels.

Inventors: KATO TAKASHI, KUREBAYASHI MASARU, TOTSUKA HAISAO, URUMA MASAAKI, YAMAMOTO MASAMI, KATO, TAKASHI, KUREBAYASHI, MASARU, TOTSUKA, HAISAO, URUMA, MASAAKI, YAMAMOTO, MASAMI
Applicants: ASAHI TEC CORP, ASAHI TEC CORPORATION
Application year: 1989
Main classification: B22C9
IPC codes: B22D15, B22C9