Support structure for fuel injection valve

A support structure for a fuel injection valve, comprising:

• a cylindrical valve housing (1) provided at a center part of a fuel injection valve (I),
• wherein an electromagnetic coil part (3) is provided at an intermediate part of the valve housing (1),
• the electromagnetic coil part (3) is covered with a synthetic resin molding portion (6),
• a coupler (14) configured to supply power to the electromagnetic coil part (3) is integrally provided on one side of the synthetic resin molding portion (6) in a protruding manner,
• a fuel nozzle cylinder part (2) of the valve housing (1) is fitted into an injection valve mounting hole (10) of an engine (E),
• a fuel supply cap (Da) of a fuel distribution pipe (D) fixed to the engine (E) is fitted onto a fuel introduction cylinder part (4) of the valve housing (1),
• an elastic support member(S) configured to bias the valve housing (1) toward the injection valve mounting hole (10) is interposed between the valve housing (1) and the fuel supply cap (Da) to form the support structure,
• the elastic support member(S) includes
• a base plate (15) having a U-shaped cutout (19) configured to accept an outer periphery of the fuel introduction cylinder part (4), and overlaid on a flat base surface (5), the base surface (5) facing the fuel supply cap (Da) and provided on a rear end surface of the synthetic resin molding portion (6) facing the fuel introduction cylinder part (4) side, and
• an elastic piece (16) extending from one end of the base plate (15) on a side opposite to the cutout (19), and configured to bring an intermediate part into resilient contact with the fuel supply cap and bring a tip part into resilient contact with the base plate (15) to apply an axial elastic force to the cylindrical valve housing (1),
• the synthetic resin molding portion (6) has a rotation-preventing protrusion (20) provided between the coupler (14) and the fuel introduction cylinder part (4) and protruding from a transition portion spanning as an extending plane extending from the base surface (5),
• the elastic support member(S) has a structure in which a pair of snap protrusions (21) snap-engaged with an outer peripheral surface of the fuel introduction cylinder part (4) accepted in the cutout (19) are each formed on both inner side surfaces of the cutout (19) of the base plate (15), and the rotation-preventing protrusion (20) is engaged with the cutout (19) and a space between tip parts (16ba) of a pair of the elastic pieces (16) simultaneously with the snap engagement,
• each of the elastic pieces (16) includes a first elastic part (16a) that is bent in a U shape laterally upward from one end of the base plate (15), and a second elastic part 16b) that extends toward the other end while being curved upward from the first elastic part (16a) and has a tip part (16ba) slidably coming into resilient contact with an upper surface of the base plate (15), and a curvature radius (R2) of the second elastic part (16b) is set to be sufficiently larger than a curvature radius (R1) of the first elastic part (16a), and
• a snap engagement force of the snap protrusion (21) with respect to the fuel introduction cylinder part (4) increases because of an increase in a contact frictional force of the elastic piece (16) against the base plate (15) caused by an increase in a flexural repulsive force of the elastic piece (16), in a mounted state of the fuel injection valve (I) on the engine (E).