High-Pressure Fuel Pump

• US 20200132029A1
• Filed: 06/25/2018
• Published: 04/30/2020
• Est. Priority Date: 07/14/2017
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: AKIYAMA, Moritsugu, USUI, Satoshi, YAMADA, Hiroyuki, OMATA, Shigehiko, NEMOTO, Masashi
• Granted Patent: US 11,248,573 B2
• Time in Patent Office: Days
• CPC Class Codes: F02M 59/025 characterised by a single piston
• CPC Class Codes: F02M 59/46 Valves
• CPC Class Codes: F02M 59/462 Delivery valves
• CPC Class Codes: F02M 59/485 Means for fixing delivery valve casing and barrel to each other or to pump casing
• CPC Class Codes: F02M 63/0036 with spherical or partly spherical shaped valve member ends
• CPC Class Codes: F02M 63/0071 characterised by guiding or centering means in valves including the absence of any guiding means, e.g. "flying arrangements"
• CPC Class Codes: F02M 63/0075 Stop members in valves, e.g. plates or disks limiting the movement of armature, valve or spring
• CPC Class Codes: F02M 63/0077 Valve seat details
• CPC Class Codes: F04B 1/0452 Distribution members, e.g. valves machines or pumps with cam-actuated distribution members at the outer ends of the cylinders F04B1/0472; machines or pumps with cam-actuated distribution members at the inner ends of the cylinders F04B1/0531; the piston-driving cams being provided with inlets and outlets F04B1/0535
• CPC Class Codes: F04B 53/1002 Ball valves
• CPC Class Codes: F04B 53/1007 having means for guiding the closure member

Abstract

Provided is a high-pressure fuel pump that ensures oil tightness even at high fuel pressure and has a small and lightweight inexpensive discharge valve structure. Therefore, a high-pressure fuel pump according to the present invention includes: a discharge valve arranged on a discharge side of a pressurizing chamber; a discharge valve seat on which the discharge valve is seated; and a facing member configured independently as a separate member from the discharge valve seat and located on an opposite side of the discharge valve seat with the discharge valve interposed therebetween, in which a stroke direction regulating portion that regulates displacement of the discharge valve in a stroke direction is formed on a tapered surface of the facing member.

Claims

1. A high-pressure fuel pump comprising:

a discharge valve arranged on a discharge side of a pressurizing chamber;

a discharge valve seat on which the discharge valve is seated; and

a facing member configured independently as a separate member from the discharge valve seat and located on an opposite side of the discharge valve seat with the discharge valve interposed therebetween,

wherein a stroke direction regulating portion that regulates displacement of the discharge valve in a stroke direction is formed on a tapered surface of the facing member.

2. The high-pressure fuel pump according to claim 1, wherein the discharge valve is configured by a ball valve.

3. The high-pressure fuel pump according to claim 2, further comprising a discharge valve chamber in which a discharge valve mechanism including the discharge valve and the discharge valve seat is arranged,

wherein the facing member is configured by a plug member (plug) that shields the discharge valve chamber from outside.

4. The high-pressure fuel pump according to claim 1, further comprising a discharge valve chamber in which a discharge valve mechanism including the discharge valve and the discharge valve seat is arranged,

wherein the facing member is configured by a discharge joint fixed to a pump body.

5. The high-pressure fuel pump according to claim 1, further comprising a discharge valve spring that is attached to the facing member and urges the discharge valve toward the discharge valve seat.

6. The high-pressure fuel pump according to claim 1, wherein a discharge valve seat member on which the discharge valve seat is formed is formed with a radial direction regulating portion that regulates displacement of the discharge valve in a direction perpendicular to a stroke axis.

7. The high-pressure fuel pump according to claim 6, wherein a radial direction flow path that causes fuel discharged via the ball valve to flow toward a radially outer side of the discharge valve mechanism is formed in the radial direction regulating portion of the discharge valve seat member on which the discharge valve seat is formed.

8. The high-pressure fuel pump according to claim 7, wherein a plurality of radial direction flow paths are formed on an outer periphery of the discharge valve seat.

9. The high-pressure fuel pump according to claim 6, wherein a length of the radial direction regulating portion in a discharge valve axis direction is formed to be approximately half or more of a diameter of the discharge valve.

10. The high-pressure fuel pump according to claim 6, wherein a length of the radial direction regulating portion is larger than a length of the tapered surface of the facing member in the discharge valve axial direction.

11. The high-pressure fuel pump according to claim 1, further comprising a relief valve mechanism that returns fuel to the pressurizing chamber or a low-pressure flow path when fuel discharged through the discharge valve exceeds a set pressure,

wherein the fuel discharged from the pressurizing chamber flows through a relief valve chamber, and then flows through a relief valve chamber in which the relief valve mechanism is arranged, and is discharged from a fuel outlet port.

12. The high-pressure fuel pump according to claim 11, wherein the fuel discharged through the discharge valve flows on a radially outer side of the discharge valve mechanism and through a flow path formed substantially horizontally in the pump body configuring the pressurizing chamber, then flows through the relief valve chamber, and is discharged from the fuel outlet port.

13. The high-pressure fuel pump according to claim 1, further comprising:

a press-fitting portion in which a discharge valve seat member on which the discharge valve seat is formed is press-fitted into the pump body; and

a welding portion in which the facing member is welded to the pump body,

wherein a discharge valve seat member on which the discharge valve seat is formed and the facing member are configured separately from each other in a non-contact manner.