Diaphragm damper, and method and device for producing the same

Abstract

A method of producing a diaphragm damper 1 having a high pressure chamber 3 comprised of two diaphragms 2 with flanges 6 welded together and charged inside with a high pressure gas. The diaphragms 2 are made of magnetically attractable thin metal sheets. A pair of jigs 30, 40 provided to face each other inside the pressure vessel 20 hold the diaphragms 2 by magnetic force. The pressure vessel 20 is sealed and evacuated, then the pressure vessel 20 is charged and pressurized by a mixed gas including helium. After this, the pair of jigs 30, 40 are made to approach each other to make the flanges 6 of the pair of diaphragms 2 come into close contact. Inside the pressure vessel 20, the jigs 30, 40 are simultaneously rotated to rotate the pair of diaphragms 2 and a laser beam is fired at the flanges 6 of the diaphragms 2 to weld the flanges 6 over their entire circumferences.

Description

TECHNICAL FIELD [0001] The present invention relates to a diaphragm damper for absorbing pulsation used in for example a high pressure fuel pump or other location where pulsation occurs and to a method of production and production apparatus for the same. BACKGROUND ART [0002] As a conventional device for absorbing pulsation of this type, the device shown in for example Japanese Patent Publication (A) No. 11-280904 is known. In the device shown in this publication, a fuel pump is equipped with a high pressure accumulator. This high pressure accumulator absorbs part of the pulsation of the pressure of the fuel discharged from the fuel pump to reduce the pulsation width of the fuel pressure and thereby stabilize the amount of injection of fuel. [0003] The high pressure accumulator shown in this publication is provided with a thick disk shaped high pressure vessel constituting a case, a thin metal disk shaped diaphragm sealed and supported by the case at its peripheral edges and working...

AI Technical Summary

Benefits of technology

[0009] Further, a second object of the present invention is to provide a diaphragm damper facilitating inspection for leakage of gas charged inside, resistant to leakage of the charged gas over a long period, and superior in reliability. MEANS FOR SOLVING THE PROBLEMS

[0036] According to the production apparatus according to the present invention, it becomes easily to realize the method of production of the present invention and becomes easy to realize the actions and effects of the method of production according to the present invention.

Problems solved by technology

However, the high pressure accumulator described in this publication has a large number of parts and is complicated in structure as well.

In production, the step of assembling and welding together the case, plate, and diaphragm and the step of charging the high pressure gas are different, so the number of steps and the number of welded parts are large and the production efficiency is poor.

However, in the method of sealing a sealed relay shown in this publication, since the metal base is placed on the flange of the metal case, the contact parts of the flange and metal base to be sealed are liable to deviate in position.

In some cases, the welding will be insufficient and will cause a poor seal.

In particular, since the laser emission unit is positioned lower than the flange of the metal case forming the seal location and the laser beam is fired at an angle from below to the flange, at parts where the metal case sticks out from the metal base, the laser beam will not sufficiently reach the metal base resulting in easy occurrence of insufficient welding.

As a result, there are the problems of easy leakage of the gas charged inside etc.

Images