Fluid handling – Line condition change responsive valves – Direct response valves
Patent
1995-05-23
1997-03-11
Nguyen, Hoang
Fluid handling
Line condition change responsive valves
Direct response valves
137550, E03B 318, F16K 1500
Patent
active
056091826
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to valves and more particularly relates to valves for radial piston pumps.
BACKGROUND OF THE INVENTION
The German patent application DE-OS 40 27 794 discloses a radial piston pump. This radial piston pump is equipped with a suction valve as well as with a pressure valve. The pressure chamber of the pressure valve is sealed by means of a cover screwed into a housing, the cover being equipped with a sealing ring. The known pressure valve further comprises a spherical valve member, a spring biassing the spherical valve member and a valve seat. Consequently, five components are needed for the functioning of the pressure valve.
The present invention is based on a much simpler design.
The object of the present invention is to simplify such a valve by reducing the number of necessary components and therefore to reduce the costs of the valve.
SUMMARY OF THE INVENTION
The present invention is based in principle on the fact, that a new connection type at the same time achieves a retaining and a sealing function so that special sealing elements are no longer necessary. Prerequisite for the effectiveness of these provisions is an insertion pressure that is high enough to make a sufficient amount of material of the shoulder run into the groove of the valve seat. The circumferential groove extends at a certain angle relative to the two circumferential surfaces of the shoulder so that the housing material running into the groove provides for an undercut relative to the outer contour. This leads on the one hand to a retaining function and on the other hand to a sealing function, since the housing material--being under pressure--fills the groove completely thus connecting the two components in a sealing and non-detachable manner.
The provisions according to the present invention can be applied in a positive way also with regard to the cover. Thus the valve seat does not only support the valve, but provides also an annular accommodation for a cover which can be pressed into the valve seat, and which can be connected with the valve seat in a sealing manner by means of cold extrusion according to the method described above. A subsequent insertion of the cover is necessary because the valve member is biassed by means of a valve spring and both elements have first to be inserted with the cover opened, before the cover can be closed.
Another type of construction with a reduced number of elements, is given in which the annular projection is omitted and the cover is not inserted this annular projection but connected, in a further step, directly with the housing by means of cold extrusion, after having mounted the valve member and the valve spring.
A further reduction of the number of components is accomplished by integrating the cover and valve seat. The problem is, however, that the valve member including spring must still be retained in this unit. This problem is solved by first equipping the unit consisting of valve seat and cover with the valve member and the biassing spring and then anchoring the equipped unit in the housing by means of cold extrusion.
The volume of the unit consisting of valve seat and cover is such that the pressure fluid generated by the pump is conducted to the outlet in the housing passing a restrictor. Therefore the pressure fluid present at the outlet of the housing shows comparatively small pressure variations since the restrictor dampens the high-pressure pulses of the pressure fluid. In this regard it must be assured, however, that the pressure fluid pumped into the valve chamber by means of the pressure valve cannot flow directly to the outlet of the housing, i.e. without passing the connection equipped with the restrictor. Thus the valve chamber is closed in a convenient manner by means of a sealed plug. It is a matter of course that, due to this additional characteristic, the number of elements necessary for the valve is higher. However, the plug, in its turn, can be pressed in a sealing manner into the unit consisting of valve seat and cover b
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Beck Erhard
Otto Albrecht
ITT Automotive Europe GmbH
Lewis J. Gordon
Nguyen Hoang
Twomey Thomas N.
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