JPH0131068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a non-return valve for low-pressure fuel delivery pumps in motor vehicles, stationary installations and the like, which comprises a valve body and an elastic valve acting in the closing direction. and a movable valve member under an initial spring force.

PRIOR ART In the case of low-pressure fuel delivery devices, common electric fuel pumps in which the pump part and the electric motor driving the pump part can be arranged axially overlapping and in a common casing are used. It is known to arrange check valves in the passages (German Patent Application No. 2,637,979). In this case, the outlet duct of the electric fuel pump is arranged in the connection piece on the discharge side of the connection housing. The connection piece on the discharge side is generally part of a closure cover manufactured from a zinc die-cast part, which closure cover is rigidly connected to the housing of the electric fuel pump, for example by a flange connection. In this case, the check valve is firmly integrated in the outlet duct of the pressure connection, the conical taper of the duct itself forming the valve seat, and as the closing member a substantially cylindrical material made of, for example, plastic viton. A mushroom-shaped valve member is pressed onto a valve seat by a valve spring. The valve spring is designed as a helical spring and is riveted by means of a steel disc into the zinc die-cast closure cover of the electric fuel pump.

In the case of electric fuel pumps of this type, which operate on the principle of a roller-type radial piston pump, the pressure fluctuations caused by the construction cause a vibrational excitation of the fuel line system by the average value of the system pressure. , the vibrational excitation leads to significant noise generation in the vehicle itself, which is extremely disturbing. The previously used check valve configurations intensify the pre-existing pressure fluctuations and thus further contribute to noise production, thus resulting in non-functional fuel delivery.

Furthermore, a disadvantage of the known construction and arrangement of check valves in electric fuel pumps is that the valve seat, which is formed by the zinc die-casting of the closing cover, is subject to a certain degree of wear and cannot be destroyed without breaking. Due to the connection with the electric fuel pump itself, which can no longer be separated, the fuel pump must be completely stopped in the event of a valve failure.

Problem to be Solved by the Invention The problem of check valves in electric fuel pumps is therefore that the vibrations caused by pressure fluctuations, which are unavoidable due to the construction, are advantageously damped without being reinforced in most cases, and at the same time The purpose is to improve requirements regarding sealing performance and pressure loss, and to make repairs easier.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, the present invention provides an interchangeable valve unit formed in two parts connected to each other and installed in a sealed manner in the pump outlet passage. Further, an elastic member connected to the valve member is formed at the same time as an adjusting member for the valve member to limit the movement of the valve member in a predetermined direction in the open operating state, and the elastic member is formed as an angled leaf spring, one end of the leaf spring is non-rotatably fixed to the valve body;
and the other end supports the valve member such that the valve member and the leaf spring are non-rotatably supported as a unit within the valve body, and the leaf spring, when assembled, positions the valve member in the open position. In this case, it was held so that it was in contact with the valve wall on one side.

Effects of the Invention The advantages obtained by the present invention are that, by restricting the degree of freedom of movement of the valve member in a check valve, pressure fluctuations that generally occur even when the entire delivery amount is allowed to flow through in an open operating state. is no longer exciting vibrations, and in some cases even provides a damping effect.

By reducing the spring movement or by reducing the spring-elastic and bendable element which exerts the initial spring force in the closing direction, the return force can also be reduced, and if this is not possible, the return force will occur. Vibration reinforcement can be completely removed.

If the valve element with the elastic element is constructed in the form of a mushroom-like closing element with a leaf spring fixed to the valve body, two functions which overlap in action and are mutually advantageous for both parties are possible. These functions are caused by the following: This means that, due to its properties, the leaf spring practically completely prevents transverse oscillating movements of the valve body and opens only a precisely predetermined opening distance for the valve member, and free oscillating movements are avoided. This is due to the fact that vibrations are hardly excited because they are damped due to the inherent slight return force of the leaf spring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 there is designated by reference numeral 1 a closing cover on the discharge side of an electric fuel pump, which is not shown because it is not part of the invention. The cover 1 has an annular flange 2 around which, as a rule, a projecting edge region of the housing of the electric fuel pump (not shown) creates an immovable, fixed valve seat. are flange-jointed. The fuel delivered by the electric fuel pump flows in this case in the direction of the arrow 3 and as long as the valve member 5 is lifted off the valve seat 7 against the pressure of the leaf spring 6 used as an elastic member. Then it flows through the check valve.

The replaceable check valve shown in the embodiment of FIGS. 2a and 2b can also be integrated into the pressure connection piece of FIG. 1. In the case of such a check valve,
The valve unit, which is manufactured separately as a component and inserted into the outlet passage of the closure cover 1, has two main parts: a first valve seat part forming a generally conically extending valve seat 7; 8 and a large valve body 9 which is connected positively and/or frictionally to the valve seat part 8.

The valve seat part 8 shown in FIG. 2a is generally injection molded as a plastic part or is made of a steel part, in which case the valve seat 7 is also made of steel and the valve seat seal is made of steel. The face is cast to a diameter suitable for a steel ball. Valve seat member 8 is the first
It has an outer annular groove 10 and a second outer annular groove or locking groove 11, the latter serving for connection with the valve body 9. Fixed groove 1
1 is provided on the outside of the valve seat member 8 at approximately the height of the inner conical valve seat area. In this case, the valve seat area is enlarged in the direction of the valve body 9 and passes into a short cylindrical section 7a. A first outer ring groove 10 in the valve seat member 8 serves to receive an O-ring 17, shown in FIG. 1, which seals the valve unit 4 to the outlet passage 16.

The valve body 9 is preferably formed from a plastic part, for example a thermoplastic injection molded part;
And when screwing into the valve unit, the inner thread 1
It has an external thread 18 in operative connection with 9. For liquid flow, the valve body 9 has lateral openings or slits, only one of which is designated by 20 in FIG. 2a. The face end of the valve body has at least one closing transverse web and preferably has an upper closing wall 21, which in this embodiment is formed by a plate. This serves for the fastening and fixed reception of the elastic element in the form of a spring 6.

As shown in FIG. 2b, the sealing member consists of its own valve member 5, which has a predominantly hemispherical mushroom-shaped member and a cylindrical-shaped member tapering upwardly. section 5a is connected. At least the mushroom-shaped part of the valve element 5 lies completely in the valve seat area 7, 7a of the valve seat element 8 in the closed position. The end of the aforementioned leaf spring 6 is connected to the valve member 5, in which case the leaf spring has a thickness in a direction perpendicular to the plane of the drawing, so that bending, torsion and tangling are prevented as shown in Figure 2a. In a direction other than that indicated by the dash-dotted line in , it is actually removed and in most cases extends with considerable slack. As shown in Figure 2a, the valve member is inserted into the valve unit 4.
When the leaf spring 6 and the valve member 5 are fitted in, the leaf spring 6 and the valve member 5 are in the position where the initial spring force is applied.

It is advantageous if the leaf spring 6 is jointly injection molded into the plastic valve body 9 and in the position shown, so that the upper part 6a of the leaf spring, which is bent horizontally in the surface plane, is tensioned. It is fixedly connected to the closing wall 21 of the valve body 9 up to the point of bending which is slightly less than a right angle in an undefined manner.
In this case, the valve member 5, which forms the closing member, is attached to the leaf spring 6 or otherwise connected to the leaf spring before the connection of the valve body 9 and the valve seat member 8, and is therefore The entire unit is formed by a leaf spring 6 and a valve member 5, which are arranged so as to be non-rotatable.
The valve body 9 and the valve seat part 8 are then pushed into each other, and the long vertical section 6c of this leaf spring 6 is bent considerably, so that the valve part 5 is raised high and pressed onto the valve seat 7. This position is shown in solid line in FIG. 2a. In this case, a plastically deformed plastic flange 9a on the valve body 9, which reaches approximately the height of the fixing groove 11, serves for the connection of the valve body 9 and the valve seat part 8; By elastically or plastically deforming both such parts surrounding the valve unit as a casing are connected to each other. During plastic deformation, the bonding takes place, for example, by inductive or conductive heating, ultrasonics, resistive heating or the like. When the non-return valve flows through, it opens in the exact aforementioned direction and along a definite stroke, i.e. a stroke which still results in only a slight tension in the leaf spring 6, depending on the type and nature of the tensioning of the leaf spring. Exercise is carried out. In this case, the displacement of the valve member takes place substantially in the direction of the arrow designated A. The displacement movement caused by the flow causes the leaf spring to move in a direction other than that which it occupies, or in a transverse direction, when the valve member 5 moves into the position indicated by the dash-dotted line in FIG. 2a. I won't let you exercise. This is because the leaf spring remains strongly tensioned in all directions of movement apart from the movement into the position shown in dash-dotted lines in FIG. 2a. Therefore, in the open state of the valve unit 4, the valve member is located in the targeted one-sided abutment in the valve wall region by the action of the leaf spring, in which case the sealing member, in other words the valve member 5, Only a small initial spring force and return force is generated in the open state, which causes it to return to its leaf spring shape. Furthermore, in the open position and during the movement into the open position as shown in FIG. .

[Brief explanation of drawings]

1 is a longitudinal sectional view of an embodiment of the check valve according to the invention, FIG. 2a is an enlarged view of the check valve according to FIG. 1, and FIG. 2b shows the valve member with the elastic member in the untensioned state. It is a diagram. 1... Closing cover, 2... Annular flange, 3...
...Arrow, 4...Valve unit, 5...Valve member, 5a
...Division, 6...Spring, 6a...Upper part, 6c
... Vertical range, 7 ... Valve seat, 7a ... Cylindrical member, 8 ... Valve seat member, 9 ... Valve body, 9a ... Flange, 10 ... First outer ring groove, 11 ...
...Fixing groove, 16...Outlet passage, 17...O ring, 18...Outer thread, 19...Inner thread, 20
...Slit, 21...Closing wall.

Claims (1)

[Claims] 1. Check valve for low-pressure fuel delivery pumps in motor vehicles, stationary installations and the like, with a valve body and a movable valve under an elastic initial spring force acting in the closing direction. in the form of an exchangeable valve unit 4 consisting of two parts 8, 9 connected to one another and mounted in a sealed manner in the pump outlet channel 16. Furthermore, an elastic member 6 that engages with the valve member 5 is formed at the same time as an adjusting member for the valve member to limit the movement of this valve member in a predetermined direction in the open operating state. Moreover, the elastic member is formed as a leaf spring 6 bent into an angular shape, one end of the leaf spring is unrotatably fixed to the valve body 9, and the other end is fixed to the valve member 9. 5 is supported such that the valve member 5 and the leaf spring 6 are unrotatably supported as a unit within the valve body 9, and furthermore, when the leaf spring 6 is assembled, the valve member 5 is in the open position. A check valve is characterized in that it is held so that it is in contact with a valve wall on one side. 2 Valve seat member 8 made of steel or plastic
has a first ring groove 10 for accommodating an O-ring 17 serving to seal the valve unit with respect to the outlet passage 16, and furthermore has a first ring groove 10 for accommodating an O-ring 17 serving to seal the valve unit against the outlet passage 16, and also for coupling the valve seat member to the valve body. Check valve according to claim 1, characterized in that it has a circulating locking groove (11) which engages a plastic flange (9a) of the body (9) which is plastically or elastically deformed.