Zexel Gmbh

Bosch Automotive Systems Corporation

Hideya Kikuchi

Etsuro Hozumi

Takeo Kushida

Nobuo Aoki

Akinao Minegishi

Fujio Aoki

Takayuki Ikeda

Katsuhiko Tsukazaki

Ken Sato

Tomoharu Sato

Koichiro Futamase

Akinori Yamazaki

Hitoshi Okuyama

Akira Kunishima

Kazumasa Kasahara

Shigeru Kashiwaba

Etsurou Hozumi

Tomiaki Hasebe

The present invention provides a pressure relief valve, which achieves a reliable sealed structure in a valve holder without the valve holder jutting far out from a common rail, assures stability of operation of a valve spring in a valve holder and is capable of being manufactured at low cost and can be made compact. A first invention relates to a pressure relief valve, which focuses on making the low-pressure portion side end portion of a valve holder a closed structure, and which has a valve spring that is housed inside the valve holder spring seats on which a valve spring is seated; a valve seat that is mounted to the valve holder and a valve body which is lifted from the valve seat by fluid pressure, this pressure relief valve being characterized in that there is formed a closed end portion which makes the low-pressure portion side end portion B of the valve holder a closed state, and, in addition, is constituted so as to enable a valve spring to be seated between the inner wall surface of closed end portion and a spring seat A second invention focuses on making the spring seats of valve spring a cup shape, and is characterized in that spring seats are housed in a slidable condition inside a valve holder as cup-shaped spring seats

Pressure relief valve

The plunger pump according to the present invention discharges fuel by reciprocation of a plunger, and comprises metallic diaphragm type dampers, provided at a fuel inlet side and a fuel outlet side, respectively, for reducing pressure pulsation of fuel. Each metallic diaphragm type damper comprises a pressure chamber for receiving fuel pressure, a back pressure chamber into which gas is charged, and a metallic diaphragm for defining the pressure chamber and the back pressure chamber. Since the metallic diaphragm type dampers are provided at the fuel inlet side and the fuel outlet side, respectively, noise and vibration caused by pressure pulsation are reduced at the fuel inlet side and the fuel outlet side. Also, since the diaphragms are metallic diaphragms, deterioration thereof generated by fuel liquid and back pressure gas is low, reliability is high, and the lifetime is long.

Plunger pump

A diaphragm type damper has a combined member, which is formed by welding a marginal portion of a diaphragm to a half body having a concave portion formed therein, and is fixed to a pressure chamber portion to which high pressure fluid is introduced. A wall thickness of a welding portion of the half body is not relevant to welding, and the heat capacity of the welding portion is small. Since the half body is allowed to have a large wall thickness, leakage from the welding portion and damage to that portion can be prevented. In addition, the diaphragm type damper of this present invention can be easily assembled, since it requires only fixing the combined member to the pressure chamber portion.

Diaphragm type damper

A communication path (32) for communicating a hermetically closed space (S) with an inlet port (20) is formed within a casing (1). An oil reservoir (30) having an inside capacity much greater than an inside capacity of the communication path (32) is formed in an intermediate part of the communication path (32).

Reciprocating pump

An externally threaded portion 31 of a valve body 10 is threadingly engaged with an internally threaded portion Hb formed on the opening portion side of an attachment hole Ha. A flange portion 32 of the valve body 10 is brought into abutment with an upper surface Hc of the housing H, so that the valve body 10 is fixed to the housing H. A lower end of the valve body 10 is located away from a bottom surface of the attachment hole Ha. A valve seat 23 and a guide hole 24 are formed inside the valve body 10. The valve seat 23 and the guide hole 24 are located on a lower side than the externally threaded portion 31. A valve element 50 is provided inside the valve body 10. This valve element 50 includes a seat portion 51 rest on the valve seat 23, and a guide portion 55 slidably engageable with the guide hole 24. A lower end opening portion of the guide hole 24 is shielded with a shielding plate 25. An orifice 25a is formed in the shielding plate 25.

Pressure control valve

A pump for low-viscosity fuel comprises a pump shaft 6 installed in a pump housing 2, 3, 4 and divided into a drive-side shaft 6A and a driven-side shaft 6B, a partition 12 provided between the drive-side shaft and the driven-side shaft of the pump shaft to prevent leakage of fuel from the housing, and a magnetic coupling 13 for transferring torque from the drive-side shaft to the driven-side shaft of the pump shaft through the partition, the magnetic coupling being disposed such that a first clearance C1, D1 between the magnetic coupling and the partition is larger than a second clearance C2, D2 between the magnetic coupling and the pump housing. When wobble occurs in the pump shaft owing to wear of the sliding contact portions thereof, the magnetic coupling makes contact with the pump housing before contacting the partition, thereby enabling the rotation of the pump shaft to be stopped before fuel leakage occurs.

Clearance means to prevent fuel leakage in a radial piston pump

A radial piston pump for low-viscosity fuel according to a first aspect of the invention comprises a pump housing, which is constituted of as few as two structural bodies (from among a drive-side housing member 2A, a fixed cylinder 81 and a cover 4), and a leaf valve member 82 which is formed with intake valves 87 for opening and closing intake side passages 27 and discharge valves 88 for opening and closing discharge side passages 28 and is sandwiched between two structural bodies (fixed cylinder 81 and cover 4). The first aspect of the invention reduces the number of components constituting the pump housing, enables highly precise overall axial alignment, prevents wobbling of a pump shaft 9 of the pump, increases performance and reliability and reduces cost. A radial piston pump for low-viscosity fuel according to a second aspect of the invention comprises a leaf valve member 205 formed in one and the same plane thereof with overflow ports communicating with an overflow passage 59 in the pump housing, intake valves 87 communicating with intake side passages 27 and discharge valves 88 communicating with discharge side passages 28. The third aspect of the invention provides a method for assembling the radial piston pump for low-viscosity fuel according to the second aspect of the invention.

Radial piston pump for low-viscosity fuel

A fuel pump for a high-pressure fuel injection system includes a high-pressure fuel pump 4 for supplying high-pressure fuel to injectors 8 for injecting high-pressure fuel into cylinders of an engine, a pressure control valve 10 for controlling the fuel pressure of the high-pressure fuel pump 4, a high-pressure fuel supply pipe 16 connecting the high-pressure fuel pump 4 and the injectors 8, a high-pressure fuel control pipe 17 connecting the injectors 8 and the pressure control valve 10, and a pump-control valve communication passage 18 formed to communicate the high-pressure fuel pump 4 with the pressure control valve 10 and bypass the injectors 8, the sectional area of the pump-control valve communication passage 18 being smaller than those of the high-pressure fuel supply pipe 16 and the high-pressure fuel control pipe 17. Owing to the provision of the pump-control valve communication passage 18, the high-pressure fuel pump of the fuel pump for a high-pressure fuel injection system can secure a pressure relief function without separate installation a relief valve.

Fuel pump for high-pressure fuel injection system

A fuel pump for a high-pressure fuel injection system is constituted by integrating into a single pump unit 15 a high-pressure fuel pump 4 for supplying high-pressure fuel to injectors 8 for injecting high-pressure fuel into cylinders of an engine 16 and a solenoid valve unit 6 for controlling the fuel pressure of the high-pressure fuel pump 4, and the pump unit 15 is adapted for mounting on the engine. The configuration decreases required installation space, enables use of a common heat installation system and reduces the number of installation steps.

A solenoid valve unit for a fuel injection apparatus suppresses fuel vaporization when the engine is being started or restarted when hot and enhances the reliability of engine operation by providing a stable fuel delivery during engine startup.

Growing community of inventors

Saitama Prefecture, Japan

Hideya Kikuchi