Fuel supply system

1. A fuel supply system comprising:

a plunger;

a housing with the plunger inserted therein so as to move backward and forward; and

a pulsation reducing mechanism arranged in the housing,

wherein the housing includes a tubular chamber provided so as to extend in a direction of the backward and forward movement of the plunger and surround an axis line of the plunger, and a pressuring chamber communicating with the tubular chamber,

the tubular chamber being a space between an inner peripheral wall, which surrounds the axis line of the plunger and extends parallel to the axis line of the plunger, and an outer peripheral wall which surrounds the axis line of the plunger and extends parallel to the axis line of the plunger,

the tubular chamber overlaps with a moving range of the plunger, in the direction of the backward and forward movement of the plunger, from a forward side end of the pressuring chamber arranged at a forward-movement side of the plunger to an end at a backward-movement side of the plunger when the plunger is moving backward,

one end portion of the plunger moving backward from and forward into the pressuring chamber,

the housing is formed by joining, at least, a first housing member forming one end side of the tubular chamber in the direction of the backward and forward movement of the plunger and a second housing member forming an other end side of the tubular chamber, and the pulsation reducing mechanism includes a tubular damper housed in the tubular chamber,

wherein:

the tubular damper includes a space between an inner peripheral portion which surrounds the axis line of the plunger and an outer peripheral portion which surrounds the axis line of the plunger,

the pulsation reducing mechanism includes a fixing member for fixing the damper to the first housing member or to the second housing member, the fixing member having a substantially L-shaped cross-sectional shape including a tubular section extending parallel to the axis line of the plunger, and a ring-like section extending radially outwardly from an end of the tubular section in a direction substantially perpendicular to the axis line of the plunger,

the inner peripheral portion and the outer peripheral portion of the damper are both operatively connected to the ring-like section of the fixing member, and

the tubular section is fixed to a surface of the inner peripheral wall or a surface of the outer peripheral wall by a press fit.

2. A fuel supply system comprising:

a plunger;

a housing with the plunger inserted therein so as to move backward and forward; and

a pulsation reducing mechanism arranged in the housing,

wherein the housing includes a tubular chamber provided so as to extend in a direction of the backward and forward movement of the plunger and surround an axis line of the plunger, and a pressuring chamber communicating with the tubular chamber,

the tubular chamber being a space between an inner peripheral wall, which surrounds the axis line of the plunger and extends parallel to the axis line of the plunger, and an outer peripheral wall which surrounds the axis line of the plunger and extends parallel to the axis line of the plunger,

the tubular chamber overlaps with a moving range of the plunger, in the direction of the backward and forward movement of the plunger, from a forward side end of the pressuring chamber arranged at a forward-movement side of the plunger to an end at a backward-movement side of the plunger when the plunger is moving backward,

one end portion of the plunger moving backward from and forward into the pressuring chamber,

the housing is formed by joining, at least, a first housing member forming one end side of the tubular chamber in the direction of the backward and forward movement of the plunger and a second housing member forming an other end side of the tubular chamber, and the pulsation reducing mechanism includes a tubular damper housed in the tubular chamber,

wherein:

the tubular damper includes a space between an inner peripheral portion which surrounds the axis line of the plunger and an outer peripheral portion which surrounds the axis line of the plunger,

the damper is a bellows damper expanding or contracting in the direction of the backward and forward movement of the plunger, the bellows damper includes an inner wall portion and an outer wall portion, the inner wall portion includes tubular mountain folds and tubular valley folds alternately in relation to a center line direction, and the outer wall portion includes tubular mountain folds and tubular valley folds alternately in relation to the center line direction.

3. The fuel supply system according to claim 2 , wherein the housing further includes a fuel channel providing communication between the pressuring chamber and the tubular chamber, and the fuel channel is formed to extend in a direction along a direction of an expanding or contracting of the damper.

4. A bellows damper for a fuel supply system, the fuel supply system including a plunger and a housing with the plunger inserted therein so as to move backward and forward, the bellows damper being arranged inside the housing,

the housing including a tubular chamber composed of a tubular space provided so as to extend in a direction of the backward and forward movement of the plunger, and a pressuring chamber communicating with the tubular chamber, one end portion of the plunger moving backward from and forward into the pressuring chamber,

the bellows damper comprising:

a tubular outer peripheral portion formed of an accordion metal thin layer;

a tubular inner peripheral portion provided on an inner peripheral side of the tubular outer peripheral portion and formed of an accordion metal thin layer;

a ring-like first end portion provided on one end side of the tubular outer peripheral portion and the tubular inner peripheral portion; and

a ring-like second end portion provided on the other end side of the tubular outer peripheral portion and the tubular inner peripheral portion;

wherein the ring-like second end portion is fixed to an end portion of the tubular chamber, and the ring-like first end portion is provided with hemispherical protrusions at an opposite side of the ring-like second end portion.

5. The bellows damper for the fuel supply system according to claim 4 , wherein the ring-like first end portion and the ring-like second end portion are formed flat like a plate.

6. The bellows damper for the fuel supply system according to claim 4 , wherein the housing includes a fuel channel providing communication between the pressuring chamber and the tubular chamber, and

the ring-like first end portion is arranged so as to oppose an opening of the fuel channel on a tubular chamber side.

7. The bellows damper for the fuel supply system according to claim 4 , further comprising a fixing member composed of,

a tubular section which fits an inner peripheral surface of the tubular chamber and which is inserted into the tubular inner peripheral portion, and

a ring-like section extending radially outwardly from an end portion of the tubular section,

wherein the ring-like second end portion is fixed to a surface of the ring-like section at a tubular section side by welding, and a surface of the ring-like section on an opposite side of the tubular section is fixed to an inner surface which is an end portion of the tubular chamber.

8. A bellows damper for a fuel supply system, the fuel supply system including a plunger and a housing with the plunger inserted therein so as to move backward and forward, the bellows damper being arranged inside the housing,

the housing including a tubular chamber composed of a tubular space provided so as to extend in a direction of the backward and forward movement of the plunger, and a pressuring chamber communicating with the tubular chamber, one end portion of the plunger moving backward from and forward into the pressuring chamber,

the bellows damper comprising:

a tubular outer peripheral portion formed of an accordion metal thin layer;

a tubular inner peripheral portion provided on an inner peripheral side of the tubular outer peripheral portion and formed of an accordion metal thin layer;

a ring-like first end portion provided on one end side of the tubular outer peripheral portion and the tubular inner peripheral portion; and

a ring-like second end portion provided on the other end side of the tubular outer peripheral portion and the tubular inner peripheral portion;

wherein the damper expands and contracts in a direction along the direction of the backward and forward movement of the plunger.