Spool valve apparatus

A spool valve apparatus comprising a drive means for generating a drive force in a first axial direction and a spool valve that includes:

• a sleeve;
• a spool that is slidably supported in the sleeve and is driven in the first axial direction by the drive means;
• a compression coil spring that urges the spool in a second axial direction, which is opposite from the first axial direction, wherein a spring diameter of an end portion of the compression coil spring, which is adjacent to the spool, is larger than an outer land diameter of a closest land of the spool, which is closest to the compression coil spring and slidably engages the sleeve;
• and
• a spring seat that contacts the spool such that the compression coil spring urges the spool in the second axial direction through the spring seat, wherein the spring seat includes:
• a cup tubular section that covers an outer peripheral surface of a distal end shaft portion of the spool;
• a cup flange section that is shaped into a flange form, which radially outwardly extends from one axial end of the cup tubular section, wherein the end portion of the compression coil spring seats against the cup flange section;
• and
• a cup bottom section that is imperforate in an axial direction so that it closes the other end of the cup tubular section and axially contacts a distal end of the distal end shaft portion of the spool to conduct a spring load of the compression coil spring to the spool, wherein the cup tubular section, the cup flange section and the cup bottom section are formed integrally, wherein:
• the distal end shaft portion of the spool includes a cylindrical outer peripheral surface that radially contacts the cup tubular section;
• and
• the cup tubular section has a cylindrical inner peripheral surface, which radially contacts the cylindrical outer peripheral surface of the distal end shaft portion of the spool.