Solenoid valve
A solenoid is operated so as to be switched between a closed valve state in which the valve element is brought into contact with the valve seat by application of a spring force and an open valve state in which an electric current is passed through a coil ( 16 ) and the valve element is separated from the valve seat by a magnetic force. A fixed iron core ( 15 ) has a U-shape, and magnetically-attracting surfaces ( 26 ) are provided on respective ends thereof. A resin case ( 17 ) into which the fixed iron core ( 15 ) and the coil ( 16 ) are incorporated is provided with a bottom surface ( 27 ) having openings through which the magnetically-attracting surfaces ( 26 ) are exposed to the outside. A case contact surface ( 51 ) protruding toward a movable element in comparison with the magnetically-attracting surfaces ( 26 ) is formed on the bottom surface ( 27 ) of the case ( 17 ). Resin films ( 52 ) are provided on the respective magnetically-attracting surfaces ( 26 ).
1. A solenoid valve which is operated so as to be switched between a closed valve state in which a valve element abuts on a valve seat by a spring member, and an open valve state in which a valve element is separated from the valve seat by a magnetic force against a spring force, the solenoid valve comprising:
a fixed iron core having a magnetically-attracting surface;
a resin case in which a coil wound around the fixed iron core and the fixed iron core are incorporated, the resin case having an opening through which the magnetically-attracting surface is exposed;
a valve body attached to the case, a movable element being housed in a movable element housing chamber which is formed between the valve body and the case, the valve body and the movable element being operated in a unified fashion;
an abutting surface which is formed in the case while protruding toward the movable element in comparison with the magnetically-attracting surface, and is opposed to the movable element; and
a resin film provided on the magnetically-attracting surface, the resin film is provided with an abutting surface adjacent to the abutting surface of the case,
wherein the abutting surface of the resin film is flush with the abutting surface of the case, or arranged so as to protrude toward the movable element in comparison with the abutting surface of the case.
2. The solenoid valve according to claim 1 , wherein the fixed iron core has a U-shape, and each end of the fixed iron core is provided with the magnetically-attracting surface.
3. The solenoid valve according to claim 2 , wherein the abutting surface of the case is provided on, at least, both sides of the abutting surface of the resin film.
4. The solenoid valve according to claim 1 , wherein the valve seat is formed on the valve body, and the movable element is provided with the valve element.
5. A solenoid valve which is operated so as to be switched between a closed valve state in which a valve element abuts on a valve seat by a spring member, and an open valve state in which a valve element is separated from the valve seat by a magnetic force against a spring force, the solenoid valve comprising:
a fixed iron core having a magnetically-attracting surface;
a resin case in which a coil wound around the fixed iron core and the fixed iron core are incorporated, the resin case having an opening through which the magnetically-attracting surface is exposed; and
a valve body attached to the case, a movable element being housed in a movable element housing chamber which is formed between the valve body and the case, the valve body and the movable element being operated in a unified fashion, the movable element having a valve element mounting surface opposite an opposing surface that opposes the resin case and having side surfaces that join the valve element mounting surface with the opposing surface;
wherein the spring member is a plate spring which has: a strip portion extending along the movable element, a leg portion arranged at one end of the strip portion, and which is held in an engaging groove of the case, and a claw portion which is fixed to the opposing surface of the movable element while covering both side surfaces of the movable element.
6. The solenoid valve according to claim 5 , wherein
a clearance is provided between the strip portion of the plate spring and the case,
a clearance is provided between an inside surface of the leg portion and an inside surface of the engaging groove, and
the leg portion is inserted into the engaging groove with an outside surface of the leg portion closely contacting an outside surface of the engaging groove.
7. The solenoid valve according to claim 5 , wherein, in the engaging groove, a guide slope is provided so that the leg portion is inserted.
8. The solenoid valve according to claim 5 , wherein the leg portion has a holding portion which extends in a width direction of the case and abuts on a bottom surface of the engaging groove, and the holding portion preventing the movable element from being inclined in a width direction.