Zexel Gmbh

Akinao Minegishi

Hideya Kikuchi

Etsuro Hozumi

Nobuo Aoki

Fujio Aoki

Hitoshi Okuyama

Akinori Yamazaki

Etsurou Hozumi

Shigeru Kashiwaba

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.

Growing community of inventors

Saitama-ken, Japan

Akinao Minegishi