Insert molded article, manufacturing method for protective cover having sensor holder part, and manufacturing method for bearing device including the protective cover

An insert molded article in which an insert article and a synthetic resin are integrated, wherein

• the insert article is formed in a cup shape,
• the cup shape has a side portion of the bottom smaller in diameter than a side portion of the cup shape to form a step connecting to a bottommost part,
• the side portion with the smaller-diameter has a concave or a convex, and
• the synthetic resin has a step covering portion that covers the step portion.

A manufacturing method for a protective cover having a sensor holder part for use in a bearing device including:

• an inner ring with an inner ring track surface on an outer periphery;
• an outer ring with an outer ring track surface on an inner periphery;
• a bearing having a rolling element rolling between the inner ring track surface and the outer ring track surface;
• a magnetic encoder that is positioned at one axial end of the bearing fixed to the inner ring, and has N and S poles alternately arranged at regular intervals in an circumferential direction;
• and a magnetic sensor that is opposed to the magnetic poles of the magnetic encoder to detect rotation of the magnetic encoder, wherein
• the protective cover has:
• a cup-shaped main part that is formed in a cup shape from a non-magnetic steel plate, positioned at the one axial end of the bearing, and press-fitted into the outer ring;
• and
• a synthetic resin sensor holder part that is integrally joined to the cup-shaped main part while holding a nut for attaching the magnetic sensor, the cup-shaped main part having a through hole in a bottom, and
• the manufacturing method comprises:
• a press working step of forming the cup-shaped main part by press working;
• and
• an injection molding step of setting the nut and the cup-shaped main part as insert articles into a metal mold, tightening the mold, charging molten plastic into a cavity to perform injection molding to form a wrap-around portion extending radially outward on an inner side of the bottom through the through hole at the sensor holder part integrated with the nut and the cup-shaped main part.

A manufacturing method for a protective cover having a sensor holder part for use in a bearing device including;

• an inner ring with an inner ring track surface on an outer periphery;
• an outer ring with an outer ring track surface on an inner periphery;
• a bearing having a rolling element rolling between the inner ring track surface and the outer ring track surface;
• a magnetic encoder that is positioned at one axial end of the bearing, fixed to the inner ring, and has N and S poles alternately arranged at regular intervals in an circumferential direction;
• and a magnetic sensor that is opposed to the magnetic poles of the magnetic encoder to detect rotation of the magnetic encoder, wherein
• the protective cover has:
• a cup-shaped main part that is formed in a cup shape from a non-magnetic steel plate, positioned at the one axial end of the bearing, and press-fitted into the outer ring;
• and
• a synthetic resin sensor holder part that is integrally joined to the cup-shaped main part while holding a nut for attaching the magnetic sensor,
• the bottom of the cup-shaped main part has a disc portion as a bottommost portion, a cylindrical portion extending axially from an outer edge of the disc portion, and an annular portion extending radially outward from an axial end edge of the cylindrical portion, the cylindrical portion having a concave or a convex, and
• the manufacturing method comprises:
• a press working step of forming the cup-shaped main part by press working;
• and
• an injection molding step of setting the nut and the cup-shaped main part as insert articles into a metal mold, tightening the mold, charging molten plastic into a cavity to perform injection molding to form a step covering portion covering a step formed by the disc portion and the cylindrical portion at the sensor holder part integrated with the nut and the cup-shaped main part.