High-pressure fuel supply pump having electromagnetically-driven intake valve
A high-pressure fuel supply pump includes a pressurizing chamber, a piston plunger, and an electromagnetically-driven intake valve mechanism. The piston plunger reciprocates within the pressurizing chamber. The electromagnetically-driven intake valve mechanism is provided at an inlet of the pressurizing chamber. The electromagnetically-driven intake valve mechanism includes an anchor which pulls a plunger rod, a fixed core which attracts the anchor, and a yoke in which inner peripheral part has the fixed core and the anchor. The fixed core is fixed to a bottom part of the yoke. A through hole is formed at a bottom part of the fixed core.
1. A fuel supply pump, comprising:
a pressurizing chamber;
a piston plunger reciprocating within the pressurizing chamber;
an electromagnetically-driven intake valve mechanism provided at an inlet of the pressurizing chamber;
an anchor;
a plunger rod;
a fixed core; and
a yoke, wherein
the electromagnetically-driven intake valve mechanism includes the anchor which pulls the plunger rod, the fixed core which attracts the anchor, and the yoke in which an inner peripheral part has the fixed core and the anchor and the inner peripheral part contacts the fixed core,
the yoke has an inner peripheral surface and a bottom surface being perpendicular to the inner peripheral surface,
the fixed core has a lower surface being located opposite to the anchor,
the lower surface of the fixed core is fixed to the bottom surface of the yoke, and
a through hole is formed at the lower surface of the fixed core.
2. The fuel supply pump according to claim 1 , wherein the fixed core is press-fitted to the inner peripheral surface of a cylindrical space of the yoke.
3. The fuel supply pump according to claim 2 ,
wherein a cylindrical hole is formed from a peripheral wall of a pump housing toward the pressurizing chamber, and
wherein the yoke is inserted from an open end of the cylindrical hole of the pump housing into an inside part of the cylindrical hole.
4. The fuel supply pump according to claim 3 ,
wherein a connecting end surface of the yoke is welded to the pump housing.
5. The fuel supply pump according to claim 1 , further comprising:
a spring biasing the plunger rod in such a direction that an intake valve is moved away from a valve seat.
6. The fuel supply pump according to claim 5 ,
wherein the spring is housed in an inner peripheral part of the fixed core.
7. The fuel supply pump according to claim 5 ,
wherein the fixed core has a cylindrical space formed inside,
wherein the spring is housed in the cylindrical space.
8. The fuel supply pump according to claim 5 ,
wherein a cylindrical space is formed inside the anchor to house the spring.
9. The fuel supply pump according to claim 8 ,
wherein the plunger rod is pulled away in a direction which is away from the intake valve when the anchor is magnetically attracted to the fixed core in opposition to the force of the spring.
10. The fuel supply pump according to claim 5 ,
wherein the anchor is magnetically attracted to the fixed core in opposition to a force of the spring at a valve closing timing of the intake valve.
11. The fuel supply pump according to claim 1 , further comprising:
a coil generating a magnetic attraction force between a surface of the fixed core and a surface of the anchor,
a cup-shaped side yoke housing the coil,
wherein the cup-shaped side yoke is press-fitted with the yoke.
12. The fuel supply pump according to claim 1 , further comprising:
a coil generating a magnetic attraction force between a surface of the fixed core and a surface of the anchor,
a cup-shaped side yoke housing the coil,
wherein a closed magnetic path across a magnetic clearance is formed around the coil by the cup-shaped side yoke, the yoke, the fixed core and anchor when the coil is electrically energized.