A high-pressure fuel pump is comprises of: a plunger which slidably fits to a cylinder and reciprocates for pressurizing and discharging a fuel taken in a pressurizing chamber; an inlet valve device for taking in a fuel into the pressurizing chamber; an outlet valve device for discharging the pressu
A high-pressure fuel pump is comprises of: a plunger which slidably fits to a cylinder and reciprocates for pressurizing and discharging a fuel taken in a pressurizing chamber; an inlet valve device for taking in a fuel into the pressurizing chamber; an outlet valve device for discharging the pressurized fuel from the pressurizing chamber; and a communicating pass which comprises a hole or a groove formed in the cylinder, and communicates between a pressurized fuel area and a gap between the cylinder and the plunger.
대표청구항▼
1. A high-pressure fuel pump comprising: a plunger which slidably fits to a cylinder and reciprocates for pressurizing and discharging a fuel taken in a pressurizing chamber;an inlet valve device for taking in a fuel into the pressurizing chamber;an outlet valve device for discharging the pressurize
1. A high-pressure fuel pump comprising: a plunger which slidably fits to a cylinder and reciprocates for pressurizing and discharging a fuel taken in a pressurizing chamber;an inlet valve device for taking in a fuel into the pressurizing chamber;an outlet valve device for discharging the pressurized fuel from the pressurizing chamber; anda communicating pass which comprises a hole or a groove formed in the cylinder, and communicates between a pressurized fuel area in the pressurizing chamber and a gap between the cylinder and the plunger;wherein the high-pressure fuel pump is configured so that a head side portion of the cylinder protrudes into the pressurizing chamber, and thereby an outer surface of the head side portion of the cylinder is located so as to contact with the pressurized fuel in the pressurizing chamber; andwherein one end of the communicating pass opens at the pressurized fuel area on an outer surface of the cylinder and the other end of the communicating pass opens on an inner surface of the cylinder where the plunger slidably reciprocates. 2. A high-pressure fuel pump according to claim 1, wherein the communicating pass comprises a hole boring in a wall of the cylinder, and wherein the inner surface of the cylinder is provided with an annular groove, and one end of the hole as the communicating pass opens in the annular groove. 3. A high-pressure fuel pump according to claim 1, wherein the communicating pass comprises a hole boring in a wall of the cylinder, one end of the hole opens on the inner surface of the cylinder having a sliding area for the plunger, the other end opens on the outer surface of the cylinder so as to communicate to the pressurizing chamber, and the one end of the hole as the communicating pass has a taper widening toward an inside of the cylinder. 4. A high-pressure fuel pump according to claim 2, wherein at least an upper end of the annular groove has a taper formed in a circumferential direction of the inner surface of the cylinder, and wherein a depth of the taper portion gradually decreases toward the pressurizing chamber. 5. A high-pressure fuel pump according to claim 1, wherein one end of the cylinder, which is on the side opposite to the pressuring chamber, is provided with a sealing device for sealing one end of the gap between the cylinder and the plunger, the sealing device is covered with a sealed space, and the sealed space communicates with a low-pressurizing chamber on an upstream side of an inlet valve of the inlet valve device. 6. A high-pressure fuel pump according to claim 1, wherein the outer surface of the cylinder has a seal portion which seals the pressurizing chamber by tightly making contact with a part of an outer surface of a pump body of the high-pressure fuel pump, and a transverse hole as the communicating pass is bored in a wall of the cylinder at the pressurizing chamber side with respect to the seal portion so as to communicate between the outer wall surface of the cylinder and the inner surface of the cylinder. 7. A high-pressure fuel pump comprising: a pressurizing chamber formed within a pump body;a cylinder fixed to the pump body;a metallic seal portion formed by a metallic contact part between a part of an outer surface of the cylinder and a part of the pump body;a plunger which slidably reciprocates on an inner surface of the cylinder to pressurize fuel taken in the pressurizing chamber and discharge pressurized fuel from the pressurizing chamber;an inlet valve device for taking the fuel into the pressurizing chamber; andan outlet valve device for discharging the pressurized fuel from the pressurizing chamber;wherein a head side portion of the cylinder protrudes into the pressurizing chamber so that the outer surface of a part of the cylinder is located so as to contact the pressurized fuel in the pressurizing chamber; andwherein the cylinder is provided with a transverse hole that, at one end, opens into the pressurizing chamber at the outer surface of the cylinder and that, at its other end, opens on the inner surface of the cylinder where the plunger slidably reciprocates. 8. A high-pressure fuel pump according to claim 7, wherein the inner surface of the cylinder on which the plunger slidably reciprocates is provided with an annular groove, and said other end of the transverse hole opens to the annular groove. 9. A high-pressure fuel pump according to claim 7, wherein an opening of said other end of the transverse hole has a taper that widens toward an inside of the cylinder. 10. A high-pressure fuel pump according to claim 8, wherein ends of the annular groove are tapered such that the annular groove widens toward an inside of the cylinder. 11. A high-pressure fuel pump according to claim 7, wherein one end of the plunger, which is on a side opposite to the pressuring chamber with respect to the cylinder, is provided with a plunger sealing device for sealing around the plunger to provide a sealed space around the plunger, and the sealed space communicates with a low-pressurizing chamber on an upstream side of an inlet valve of the inlet valve device. 12. A high-pressure fuel pump according to claim 11, further comprising a cylinder holder, which holds the plunger sealing device and a part of the cylinder on the side opposite to the pressurizing chamber, wherein the cylinder holder is fixed to the pump body to provide for installation of the plunger sealing device and the cylinder to the pump body. 13. A high-pressure fuel pump according to claim 7, wherein a part of a fuel channel on a low-pressure side of the fuel pump is provided outside the pressurizing chamber so as to be covered with a damper cover, a damper chamber for a damper which absorbs a fuel pressure pulsation is formed by the damper cover, and the fuel on the low-pressure side is guided to the inlet valve side through the damper chamber. 14. A high-pressure fuel pump according to claim 7, wherein, in the cylinder, a length from the metallic seal portion to one end at the pressurizing chamber side is longer than a length from the metallic seal portion to the other end opposite to the pressurizing chamber side. 15. A high-pressure fuel pump according to claim 7, wherein the one end of the plunger protrudes into the pressurizing chamber through the cylinder. 16. A high-pressure fuel pump according to claim 8, wherein the annular groove is located at a middle point of the cylinder. 17. A high-pressure fuel pump according to claim 7, wherein the outlet valve is installed from a pressurizing chamber side into the pump body. 18. A high-pressure fuel pump according to claim 7, wherein the pump body is provided with the outlet valve by installation from a pressurizing chamber side in the pump body, and a horizontal mounting hole for the outlet valve device is designed to have a smaller diameter than the diameter of a horizontal mounting hole for the inlet valve device.
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이 특허에 인용된 특허 (1)
Asayama,Kazuhiro; Ishikawa,Tomoji; Kurata,Naoki; Yamazaki,Daichi; Sugiyama,Masanori; Inoue,Hiroshi, High-pressure fuel pump and assembly structure of high-pressure pump.
Matsumoto, Teppei; Kuroyanagi, Masatoshi; Hishinuma, Osamu, High pressure pump with pressurizing chamber enclosed within cylinder inserted into housing.
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