Abstract: A worm wheel of a reduction gear for an electric power steering includes: a boss part including a hollow portion formed along an axial-direction center for coupling of a shaft and having first coupling surfaces, each of which is formed by a first convex surface and a first concave surface continuously repeated along an outer peripheral surface; and a tooth-shaped part having second coupling surfaces, each of which is formed by a second convex surface and a second concave surface continuously repeated along an inner peripheral surface, such that the second coupling surfaces are coupled corresponding to the first coupling surfaces, wherein a plurality of teeth are continuously formed along a periphery thereof with spacing portions interposed therebetween.

Abstract: A worm wheel of a reduction gear for an electric power steering includes: a boss part including a hollow portion formed along an axial-direction center for coupling of a shaft and having first coupling surfaces, each of which is formed by a first convex surface and a first concave surface continuously repeated along an outer peripheral surface; and a tooth-shaped part having second coupling surfaces, each of which is formed by a second convex surface and a second concave surface continuously repeated along an inner peripheral surface, such that the second coupling surfaces are coupled corresponding to the first coupling surfaces, wherein a plurality of teeth are continuously formed along a periphery thereof with spacing portions interposed therebetween.

Abstract: A reduction gear for electric power steering includes a first reduction gear composition for electric power steering containing 95 to 97 parts by weight of polyamide 66 (PA66) among polyamide-based materials, and a second reduction gear composition for electric power steering containing 3 to 5 parts by weight of an ethylene-methacrylic acid copolymer (EMAA) among polyolefin-based materials, wherein a weight ratio of the PA66 to the EMAA is 24:1 to 49:1. A method for manufacturing a reduction gear for electric power steering includes adding a first reduction gear composition for electric power steering comprising 95 to 97 parts by weight of PA66 among polyamide-based materials and a second reduction gear composition for electric power steering containing 3 to 5 parts by weight of an EMAA among polyolefin-based materials to a heater having a melting temperature of 250° C. to 260° C.

Abstract: Disclosed is a worm wheel of a reducer of an electric power steering apparatus which is manufactured by integrally injection-molding a hub, a boss, and a gear forming part, thereby making it possible to increase a forming performance of the worm wheel and reduce an amount of material, and increasing a mechanical durability and frictional characteristics of the worm wheel to allow the reducer to be stably used for a long time, and a method for manufacturing the same.

Abstract: The present invention provides a plasmid for expressing a thioredoxin fusion protein comprising thioredoxin as a fusion partner, an E. coli cell transformed with the plasmid, and an efficient method for producing a target protein using the E. coli cell. The method according to the present invention can easily remove thioredoxin from thioredoxin fusion protein, so that can produce a target protein of interest in pure and large quantities in the field of medicine and bioengineering.