Patent ID: 11885431
Assignee: TRINITY INDUSTRIAL CORPORATION
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  B | IPC F

Claim 5:
6. A valve-device comprising:
a housing-block having a piston-housing chamber and a valve-seat inside,
a valve-rod of which a part thereof is inserted into the piston-housing body, and
a piston is provided in the region located inside the piston-housing chamber, and a valve is formed in the region located outside the piston-housing chamber,
wherein, the valve-rod is driven in a first direction by air pressure of pilot-air acting upon the piston, and is driven in a second direction opposite the first direction by a biasing-force of a spring as a biasing-means; then the valve makes contact with and separates from a valve-seat by supplying and discharging the pilot-air, between the opening and closing of the valve, characterized the valve-body comprising:
a first-magnet holder provided at an outer periphery of the piston;
a second-magnet holder provided at a position facing the first-magnet holder on a housing-block side;
a first-permanent magnet held by the first-magnet holder in a state in which an end-face thereof makes contact with a thin-walled first-collision-avoidance portion formed at a position closest to the second-magnet holder; and
a second-permanent magnet held by the second-magnet holder in a state in which an end-face thereof makes contact with a thin-walled second-collision-avoidance portion formed at a position closest to the first-collision-avoidance portion of the first-magnet holder;
wherein, a magnetic-attraction force acts between both first- and second-permanent magnets, and drives the piston in the first direction, and increases with a mutual approach of both first- and second-permanent magnets; in addition, an arrangement-relationship is set between both first- and second-permanent magnets such that the end-faces thereof do not directly collide with each other, even when they are closest to each other, and
wherein each of the first-permanent magnet and the second-permanent magnet is an annular-permanent magnet of the same-diameter and is magnetized in a thickness direction and the first-permanent magnet or the second-permanent magnet is arranged in multiple stages in the thickness direction by using a plurality of magnets.