Ground coil device for magnetic levitation railway and method for manufacture thereof
A ground coil device for a magnetic levitation railway that can be manufactured with a high productivity and exhibit less fluctuation in strength, reduced weight, and good recyclability, and a process for manufacturing the device. The ground coil device includes a coil conductor covered with a thermoplastic resin molding material containing 100 parts by mass of a thermoplastic resin, from 20 to 200 parts by mass of an inorganic filler, and from 0 to 25 parts by mass of an elastomer. A process for producing the ground coil device for magnetic levitation railway includes filling the thermoplastic resin molding material into a cavity of a metal mold into which the coil conductor is previously inserted, by an injection molding method, to obtain an integrally molded product.
1. A ground coil device for a magnetic levitation railway affixed to a side wall of a concrete track, comprising:
a coil conductor covered with a thermoplastic resin molding material having (A) 100 parts by mass of a thermoplastic resin, (B) from 20 to 200 parts by mass of an inorganic filler, and (C) from 0 to 25 parts by mass of an elastomer; and
a metal bush embedded in the ground coil device at a position corresponding to a fitting bolt for mounting the ground coil device to the side wall of the concrete track,
wherein the ground coil device has a boss-shaped portion corresponding to the fitting bolt for mounting the ground coil device to the side wall of the concrete track, and 8 or more ribs each having a thickness of from 1.5 to 10 mm at a tip end thereof and a height of 30 mm or more that are connected to the boss-shaped portion.
2. A process for manufacturing a ground coil device for a magnetic levitation railway, the ground coil device affixed to a side wall of a concrete track, the ground coil device having a coil conductor covered with a thermoplastic resin molding material having (A) 100 parts by mass of a thermoplastic resin, (B) from 20 to 200 parts by mass of an inorganic filler, and (C) from 0 to 25 parts by mass of an elastomer, the process comprising:
filling the thermoplastic resin molding material into a cavity of a metal mold into which the coil conductor is previously inserted, by an injection molding method, to obtain an integrally molded product,
wherein the coil conductor is fixed in the metal mold by pins configured to advance into and retreat from the metal mold, and wherein the pins configured to advance into and retreat from the metal mold are each fitted at a tip end thereof with an insulating member.
3. The ground coil device for a magnetic levitation railway according to claim 1 , wherein the thermoplastic resin as the component (A) of the thermoplastic resin molding material is a polyarylene sulfide-based resin.
4. The ground coil device for a magnetic levitation railway according to claim 1 , wherein the inorganic filler as the component (B) of the thermoplastic resin molding material has a fiber shape, a spherical shape, a plate shape, or an amorphous shape.
5. The ground coil device for a magnetic levitation railway according to claim 1 , wherein the device has a generally flat surface on a side facing a vehicle and a swelled surface corresponding to a shape of the coil conductor on a side facing the side wall, and comprises ribs disposed in an inner diameter portion of the coil conductor.
6. The ground coil device for a magnetic levitation railway according to claim 1 , wherein the metal bush includes opposite ends thereof with jaws having different diameters from each other.
7. The process according to claim 2 , wherein the process is conducted using an injection molding machine equipped with a mold clamping device that is operated in a direction parallel with a gravity direction.
8. The process according to claim 2 , wherein the coil conductor comprises coil wires fixedly bonded together with a thermosetting resin.
9. The process according to claim 2 , wherein after the thermoplastic resin molding material is filled into the cavity of the metal mold before a temperature of the thermoplastic resin molding material is decreased below a temperature at which the molding material is flowable, the pins are retreated from the metal mold, and portions from which the pins are retreated are filled with the thermoplastic resin molding material to produce a stepless molded product.