Abstract: A damper device is provided in a flow passage of a fluid. The damper device includes a plurality of diaphragm dampers that are stacked together. Each of the plurality of diaphragm dampers includes a first flexible portion, a second flexible portion, and a rim including a welded portion. A peripheral edge of the first flexible portion and a peripheral edge of the second flexible portion are welded together in the welded portion. Each of the plurality of diaphragm dampers is configured to seal a gas in an inner region between the first flexible portion and the second flexible portion. A coupler that couples the plurality of diaphragm dampers together includes holders that hold the rims of the plurality of diaphragm dampers. A gap is provided between the holder of the coupler and the welded portion of each of the plurality of diaphragm dampers.

Abstract: A pulsation damper includes an upper diaphragm, a lower diaphragm configured to form a sealed space having a predetermined pressure with the upper diaphragm, in which an inert gas is filled; and a deformation suppressing member formed of an elastic material, and comprising an inner cylindrical portion, and an extension portion extending from a center portion on an outer peripheral surface of the inner cylindrical portion such that the extension portion extends outward from a center axis of the inner cylindrical portion, wherein the deformation suppressing member is arranged inside the sealed space such that an outer periphery of the extension portion abuts against inner walls of the upper diaphragm and the lower diaphragm.

Abstract: A diaphragm includes a flange and a protrusion provided to protrude to one side of the flange, wherein the protrusion has at least two annular curved portions provided annularly on a ceiling portion having a flat surface-like shape and an outer side in a radial direction of the ceiling portion, in a state where pressure on an outer wall side of the protrusion and pressure on an inner wall side of the protrusion are the same, the at least two annular curved portions are each formed to be curved in a cross-section of the diaphragm obtained by cutting the diaphragm by a virtual plane including a center line of the diaphragm, the centers of curvature of the curved portions being arranged at different positions on a side opposite to a protruding direction of the protrusion, and the diaphragm is formed of a sheet metal.

Abstract: A pulsation damper includes an upper diaphragm, a lower diaphragm configured to form a sealed space having a predetermined pressure with the upper diaphragm, in which an inert gas is filled; and a deformation suppressing member formed of an elastic material, and comprising an inner cylindrical portion, and an extension portion extending from a center portion on an outer peripheral surface of the inner cylindrical portion such that the extension portion extends outward from a center axis of the inner cylindrical portion, wherein the deformation suppressing member is arranged inside the sealed space such that an outer periphery of the extension portion abuts against inner walls of the upper diaphragm and the lower diaphragm.

Abstract: A damper device is provided in a flow passage of a fluid. The damper device includes a plurality of diaphragm dampers that are stacked together. Each of the plurality of diaphragm dampers includes a first flexible portion, a second flexible portion, and a rim including a welded portion. A peripheral edge of the first flexible portion and a peripheral edge of the second flexible portion are welded together in the welded portion. Each of the plurality of diaphragm dampers is configured to seal a gas in an inner region between the first flexible portion and the second flexible portion. A coupler that couples the plurality of diaphragm dampers together includes holders that hold the rims of the plurality of diaphragm dampers. A gap is provided between the holder of the coupler and the welded portion of each of the plurality of diaphragm dampers.

Abstract: A partitioning portion partitions a fuel chamber into a first space, which receives a pressurizing chamber forming portion and is communicated with an inflow pipe, and a second space, which is communicated with an outflow pipe. A flow passage forming portion extends from the partitioning portion toward the first space side and forms a communicating flow passage, which communicates between the first space and the second space. Thereby, vapor contained in the fuel, which is returned from a pressurizing chamber to the fuel chamber, is accumulated as bubbles in the first space, which receives the pressurizing chamber forming portion. The first space is communicated with the outside through the communicating flow passage and the second space. Therefore, outputting of air bubbles of the first space to the outside can be effectively limited in comparison to a case where the fuel chamber is directly communicated with the outside.

Abstract: A diaphragm includes a flange and a protrusion provided to protrude to one side of the flange, wherein the protrusion has at least two annular curved portions provided annularly on a ceiling portion having a flat surface-like shape and an outer side in a radial direction of the ceiling portion, in a state where pressure on an outer wall side of the protrusion and pressure on an inner wall side of the protrusion are the same, the at least two annular curved portions are each formed to be curved in a cross-section of the diaphragm obtained by cutting the diaphragm by a virtual plane including a center line of the diaphragm, the centers of curvature of the curved portions being arranged at different positions on a side opposite to a protruding direction of the protrusion, and the diaphragm is formed of a sheet metal.

Abstract: A partitioning portion partitions a fuel chamber into a first space, which receives a pressurizing chamber forming portion and is communicated with an inflow pipe, and a second space, which is communicated with an outflow pipe. A flow passage forming portion extends from the partitioning portion toward the first space side and forms a communicating flow passage, which communicates between the first space and the second space. Thereby, vapor contained in the fuel, which is returned from a pressurizing chamber to the fuel chamber, is accumulated as bubbles in the first space, which receives the pressurizing chamber forming portion. The first space is communicated with the outside through the communicating flow passage and the second space. Therefore, outputting of air bubbles of the first space to the outside can be effectively limited in comparison to a case where the fuel chamber is directly communicated with the outside.

Abstract: A pulsation dumper configured to reduce a fuel pressure pulsation of fuel flowing in a fuel chamber includes a sealed space in which gas having a predetermined pressure is encapsulated between a first diaphragm and a second diaphragm configured to be resiliently deformable by a fuel pressure pulsation in the fuel chamber. A first resilient member provided in the sealed space abuts against an inner wall of the first diaphragm, and a second resilient member abuts against an inner wall of a second diaphragm. A supporting member provided between the first resilient member and the second resilient member supports an outer peripheral portion of the first resilient member and an outer peripheral portion of the second resilient member. A resonance of first and second diaphragms is restrained by the first and second resilient members. The first and second resilient members do not impair deformation of center portions of the first and second diaphragms.

Abstract: In a housing, a damper member is placed in a fluid chamber communicated with a pressurizing chamber, at which a plunger is reciprocated to pressurize fuel, and an opening of the fluid chamber is covered with a cover member. The damper member includes first and second-side diaphragms. A first-side support member is located between the damper member and the cover member and is engaged with a first-side outer peripheral portion of the first-side diaphragm and the cover member. A second-side support member is located between the damper member and the housing and is engaged with a second-side outer peripheral portion of the second-side diaphragm and the housing. The first and second-side support members are urged between the housing and the cover member.

Abstract: In a housing, a damper member is placed in a fluid chamber communicated with a pressurizing chamber, at which a plunger is reciprocated to pressurize fuel, and an opening of the fluid chamber is covered with a cover member. The damper member includes first and second-side diaphragms. A first-side support member is located between the damper member and the cover member and is engaged with a first-side outer peripheral portion of the first-side diaphragm and the cover member. A second-side support member is located between the damper member and the housing and is engaged with a second-side outer peripheral portion of the second-side diaphragm and the housing. The first and second-side support members are urged between the housing and the cover member.

Abstract: In a fuel injection valve, an adjustment pipe made of stainless steel and for adjusting a compression amount of a spring biasing a valve member is press-fitted into a cylindrical housing made of stainless steel, and a fuel injection amount is adjusted by adjusting a spring force of the spring in accordance with a press-fitted amount of the adjustment pipe. The adjustment pipe is immersed in an oxalic acid solution so that an oxalate film is formed thereon before being press-fitted into the cylindrical housing. Therefore, the oxalate film prevents a direct press-contact between an outer peripheral surface of the adjustment pipe and an inner peripheral surface of the cylindrical housing.

Abstract: In a fuel injection valve, an adjustment pipe made of stainless steel and for adjusting a compression amount of a spring biasing a valve member is press-fitted into a cylindrical housing made of stainless steel, and a fuel injection amount is adjusted by adjusting a spring force of the spring in accordance with a press-fitted amount of the adjustment pipe. The adjustment pipe is immersed in an oxalic acid solution so that an oxalate film is formed thereon before being press-fitted into the cylindrical housing. Therefore, the oxalate film prevents a direct press-contact between an outer peripheral surface of the adjustment pipe and an inner peripheral surface of the cylindrical housing.

Abstract: A cylinder screw is fitted around an injector axially movably between a tapered surface and a flange. The cylinder screw presses down the flange in a direction to attach the injector to a cylinder head and presses up the tapered surface in a direction to detach the injector from the cylinder head. A stopper is formed annularly at the top of the injector and has a protrusion. With the protrusion being engaged in a positioning groove of the cylinder head, the injector is restricted from being turned in both rotating directions. Thus, the injector can be attached to and detached from the cylinder head with ease by only one cylinder screw without turning the injector. The flange of a retaining nut to which the tightening force of the cylinder screw exerts has a shortened axial length so that deformation in injector constituting members is reduced and changes in the fuel injection characteristics are reduced.