Patent ID: 9018945
Filing Date: 2015-04-28
Classification: B29C,B29K,G01D,G01L

Abstract:
1. A relative angle sensing device that senses a relative angle between two rotary shafts comprising: a hard magnetic body that is provided to one rotary shaft out of the two rotary shafts; a soft magnetic body that is provided to the other rotary shaft out of the two rotary shafts to be arranged in a magnetic field formed by the hard magnetic body, and forms a magnetic circuit together with the hard magnetic body; and a sensing unit that senses a magnetic flux density of the magnetic circuit, wherein the soft magnetic body is formed by injection molding by using a material obtained by mixing a magnetic powder and a synthetic resin, a bracket that is integral to the soft magnetic body, the bracket including a first portion that is embedded within the soft magnetic body and a second portion that fixes the soft magnetic body to the other rotary shaft, and wherein the soft magnetic body has a circular ring portion that is formed into a disc having, at an inside thereof, a hole larger than an outer shape of the hard magnetic body, and a protrusion that is formed to protrude from a section of the circular ring portion at a hard magnetic body side in a shaft direction of the one rotary shaft, and distance from an outer section of the protrusion to the hard magnetic body increases from a tip end portion side toward the circular ring portion, and distance from an inner section of the protrusion to the hard magnetic body is substantially the same from the tip end portion side toward the circular ring portion.