DE2121637A1 - DIAPHRAGM PUMP, IN PARTICULAR FUEL PUMP FOR COMBUSTION ENGINES - Google Patents

Description

A. Pierburg

Autogerätebau KG.

HOKO H euss
Düsseldorfer Strasse 232

Diaphragm pumps, in particular fuel pumps for internal combustion engines

The invention relates to a diaphragm pump, in particular Fuel pump for internal combustion engines, with a multi-part housing that has a suction space, a work space and forms a pressure space for the medium to be conveyed and with a working diaphragm which the working space against a Actuating space closes. The diaphragm pump has a hood-like design, equipped with a suction valve and a pressure valve Partition between the work area and the pressure area. It has another partition between the pressure chamber and the suction gravel. This partition is provided with an opening located above the suction valve. Also has the diaphragm pump a hood that covers the suction chamber and has a central bore for receiving a fastening screw.

These diaphragm pumps are preferably used to deliver the fuel required to operate an internal combustion engine. They are usually driven mechanically by the engine itself, e.g. by means of levers or plungers.

One such, driven by rocker arms and camshaft Diaphragm pump is known from French Patent No. 1 if50 325.

309824/001 1

There have been "in the operation of the known diaphragm pumps for Promotion of fuel for internal combustion engines result in disadvantages. The partition between the suction chamber and the pressure chamber has namely a threaded hole in which the fastening screw of the suction chamber cover engages. Will this If the fastening screw is tightened, the partition wall and the elastically deformable parts that make up the suction space are deformed Seal against the pressure chamber and the outside air, are no longer able to compensate for the deformation. you will be permeable at the edges. The more tightly the screw is tightened, the leaky the diaphragm pump will be. If you loosen it If you screw again, the elastic tension that presses the parts together is reduced and the leaks remain exist. Another leak is caused by the connection of the suction chamber with the pressure chamber along the thread grooves Fixing screw available. Due to the central bracing of the suction chamber cover hood with the partition between In addition, this partition is inadmissibly stiffened in the suction chamber and pressure chamber. She is no longer elastic enough that to compensate for periodic pressure peaks occurring during operation of the pump. The consequence of this is that already in the pump The formation of vapor bubbles occurs at an early stage as the fuel temperature rises, which can lead to malfunctions in the Fuel supply and sometimes even pump failure leads.

The aim of the invention is to reliably seal the pump chambers to improve, to prevent premature vapor lock formation and to avoid the disadvantages described.

This purpose is achieved according to the invention in that a tube, which is plastically and elastically deformable in the longitudinal direction, The partition between the suction chamber and the pressure chamber and the partition between the pressure chamber and the working chamber are hermetically sealed sealingly and inextricably linked in such a way that for the

309824/001 1

Passage of the medium to be conveyed creates a connection between the suction chamber via the suction valve to the working chamber of the diaphragm pump through the pressure chamber. This piece of pipe compensates for manufacturing tolerances through plastic deformation during assembly smaller movements and vibrations are elastic. It is expediently made of sheet metal, if the length is greater wavy and with flared edges. By It is permanently connected to the partition walls by welding, soldering or gluing.

The invention is particularly effective when below the central bore of the suction chamber cover hood in the suction chamber, a fastening plate provided with a threaded bore is not present, which is connected to the edge of the hood-like partition between the pressure chamber and the suction chamber, and that the fastening screw of the suction chamber cover engages in the threaded hole. It is useful between the suction chamber cover hood and the fastening plate a stop element limiting the screw-in depth of the fastening screw arranged. This can be, for example, a sleeve, washer or other that rests on the mounting plate or be connected to it, a stop surface forming protrusion. When tightening the fastening screw you can now neither the partition between the suction chamber and the pressure chamber nor the suction chamber cover are deformed in an impermissible manner.

The invention requires an arrangement of the filter arranged on the inlet side which deviates from the usual scheme for the medium to be promoted. The inlet connector expediently penetrates the wall laterally below the mounting plate the suction chamber cover. A filter element is slipped onto the inwardly protruding inlet connection.

The advantages of the invention are in particular that due to manufacturing tolerances, material aging and others

30982 4/0011

Reasons no leaks between the suction chamber and pressure chamber can occur that the partition between the suction chamber and pressure chamber maintains its elasticity and is therefore able to compensate for pressure peaks during operation, which results in a reduced tendency to form vapor bubbles. The suction chamber cover can no longer be impermissible are severely deformed, so that there is a risk of them leaking by improperly tightening the fastening screw is, at least greatly reduced. An embodiment of the invention is shown in the drawing and is in is described in more detail below.

The drawing shows a section through a diaphragm pump according to the invention. The housing of this pump is constructed in several parts and consists of the lower part 1 with a cast-on flange 2, as well as other individual parts. The working diaphragm 3 with the diaphragm plates k and 5 closes off the working space 6 of the pump from the actuating space 7. A plunger 8 is used to actuate the working diaphragm 3. The pressure chamber 9 is closed off from the working chamber 6 by a partition 10. The partition 10 is hood-like and has a circular, outwardly beaded edge, which has a slightly smaller diameter than the edge 11 of the lower housing part 1. The partition 10 has two openings ¹ 2 and 13 above the opening 12 is that arranged as a plate valve pressure valve 1 **. The suction valve 15 with its resilient metal tongue 16 and the tongue stop 17 is seated under the opening 13.

Another partition 18 is arranged between the pressure chamber and the suction chamber. It covers the partition wall 10 like a hood, presses whose beaded edge is sealing against the working diaphragm 3 and 1 resting on the edge 11 of the lower housing part 8 even with its edge 19 sealing around the edge 11 of the lower housing parts 1 flanged.

309824/0011

The partition 18 has a located above the suction valve 15 Opening 20. According to the invention, the pipe section 21, which is plastically and elastically deformable in the longitudinal direction, connects the partition walls 10 and 18 in a hermetically sealing and non-detachable manner to one another, that a connection between the suction chamber 22 via the suction valve for the passage of the medium to be conveyed 15 to the working chamber 6 of the diaphragm pump through the pressure chamber 9 exists through it.

The pipe section 21 is made of tinned metal, has flared edges and is soldered to the Partitions connected. -

A hood 23 forms the outer closure of the suction space 22. Its beaded edge 2h carries the inserted sealing ring 25, with the aid of which the suction space 22 is sealed from the outside.

The hood 22 has a central bore for receiving the fastening screw 26 and the sealing ring 27 · The fastening screw 26 engages in the ^; Thread turns of the fastening plate 28 arranged according to the invention, which is connected to the upper edge 31 of the partition wall 18 by the webs 29 and 30. Instead of the webs 29 and 30, a perforated hood can also be arranged; a stop element 35 in the form of a disk is arranged above the fastening plate 28. When choosing the pane thickness, manufacturing tolerances of the components to be connected can be taken into account and compensated for. '- ■ "- -

The inlet port 32 for the medium to be conveyed penetrates the side wall of the Saugrauraabdeckhaube 23 below the Mounting plate 28. over the inner end of the Inlet connection 32, the filter element 33 is inserted;

The outlet connection Jh is arranged in the side wall of the partition wall 10 in the vicinity of the pressure valve I ^. . r

BAD ORJGJNAL 3 09824/0011;

Claims (1)

Claims Ql) diaphragm pumps, especially fuel pumps for internal combustion engines, with a multi-part housing that has a suction chamber, a working chamber and a pressure chamber for forms the medium to be conveyed, with a working diaphragm which closes the working space from an actuating space, with a hood-like partition, equipped with a suction and a pressure valve, between the working space and the pressure space, with a hood-like covering this partition wall between the pressure chamber and suction chamber, which provided with an opening above the suction valve k, with a hood covering the suction space, is the one has a central hole for receiving a fastening screw, characterized. that a pipe section (21) which is plastically and elastically deformable in the longitudinal direction, hermetically sealing both partition walls and inextricably linked in such a way that a connection between the suction chamber (22) for the passage of the medium to be conveyed exists via the suction valve (15) to the working chamber (6) of the diaphragm pump through the pressure chamber (9). 2) diaphragm pump according to claim 1, characterized in that the pipe section (21) made of sheet metal and has outwardly flared edges. 3) diaphragm pump according to claim 1 and 2, characterized in that the pipe section (21) through Welding, soldering or gluing is connected to the partition walls (10, 18). h) Diaphragm pump according to claim 1 to 3, characterized in that below the central bore of the Saugraumabdeckhaube (23) in the Saugraura (22) a mounting plate (28) provided with a threaded hole is present, which with the edge (31) of the hood-like separating 3098 2 4 / 0.0 11 wall [Λ 8, is connected between the pressure chamber (9) and the suction chamber (22), and that the fastening screw (26) of the suction chamber cover hood (23) engages in the threaded hole. 5) Diaphragm pump according to claim 1 to k, characterized in that a stop element (35) limiting the screw-in depth of the fastening screw 26 is arranged between the Seugraumabdeckhaube (2J-) and the fastening plate 28. 6) Diaphragm pump according to claim 1 to ^ _Λ, characterized in that the inlet port (32) for the medium to be conveyed laterally below the mounting plate (28) penetrates the wall of the suction chamber cover (23) and carries an attached filter element (33). 309824/0011 BATH ORIGINAL Blank page