DE19827293A1 - Piezoelectric hydraulic pump for delivering fuel - Google Patents

Abstract

The pump has a piezoelectric stack (9) axially oscillating a piston (7) having a bored (16) stem (2) connecting to the chambers (19) through bores (21). Each chamber comprises a membrane (4) and sealing ring (20). Successive movement draws in (14) fluid and delivers it through a valve (1).

Description

The invention relates to an electrohydraulic pump and drive element in the preamble of claim 1 specified Art.

Electrohydraulic pump and drive elements have been widely used and are manufactured in a variety of technologies.

Devices of the type mentioned work with piezoelectric, magneto strictive or electrostrictive actuators as drive elements that directly or indirectly act on a piston or a membrane, the piezo stack and the piston or the Diaphragm should be as large as possible to achieve an effective secondary travel or to be able to spray the necessary amounts of fuel, as z. B. from DE 196 19 319 A1 is known.

Starting from this prior art, the invention is based on the object the most rigid, small-sized, low-wear, cavitation-free and liquid-tight Device with good dynamic properties, especially with high operating fre sequences and with an effective secondary travel range or a precisely controllable and reproducible sprayable spraying of the total required fuel quantities or their partial quantities, with the smallest possible piezo stack using a device in the preamble of To create claim 1 type.

This object is achieved by the characterizing features of claim 1.

Advantageous developments of the invention are dependent on this claim Claims marked.

In the following, the invention is based on a preferred embodiment in Connection described with four drawings. It shows:

Fig. 1 is a simplified sectional drawing. The electrohydraulic drive element is used here as a pump-nozzle unit (PDE). The drive element ( 9 ), in a preferred embodiment as a piezo ring stack, acts on the abutment piston ( 7 ) which is integrally connected to the piston rod ( 2 ) and the ring membranes ( 4 .. .N) and the smaller ones the ring webs ( 5 .. .n) attached ring sealing membranes ( 20 .. .n) moved forward with active piezo element, with the pump chambers ( 19 ...) filled with fuel or another fluid via the bores ( 21 .. .n) .n) are emptied through the piston rod bore ( 16 ) in the direction of the valve ( 1 ). Due to the series-connected and in fluid communication with each other pumping chambers ( 19 .. .N) one is relatively independent of the length of the piezo actuator and the ring diaphragm diameter. The ring membranes ( 4 .. .N) can also lie directly against the walls of the ring webs ( 5 .. .N) in order to accommodate more pumping chambers ( 19 ).

Fig. 2 shows an embodiment as a lifting transformer, the pump chambers filled with hydraulic oil ( 26 .. .N) through the blind hole ( 27 ) and the bellows ( 30 ) acts on the element ( 23 ), the bellows ( 30 ) with the piston rod ( 29 ) and the position element ( 23 ) is non-positively or positively connected.

Fig. 3 shows an embodiment in which the control element ( 23 ) with its piston ( 33 ) runs in the cylinder bore ( 36 ). Here the annular chamber ( 35 ) is completely or partially filled with hydraulic oil.

Fig. 4 shows an embodiment in which the bellows ( 39 ) acts on the pump membrane ( 38 ), with which it can also be non-positively or positively connected. To compensate for the thermal expansion, the pressure compensation chamber ( 46 ) is in flow connection via the connecting channel ( 44 ) and the metal sieve ( 45 ) and is filled with a homogeneous or more lumpy substance with a negative temperature coefficient.

Reference list

1

Valve

2nd

Piston rod

3rd

casing

4th

Ring membrane

5

Ring bridge

6

Spring plate membrane

7

Abutment piston

8th

cylinder

9

Drive element

10th

Ball disc ring

11

Valve

12th

Lock nut

13

Adjustment cylinder

14

Connecting thread

15

Adjustment cylinder bore

16

Piston rod bore

17th

Adjustment cylinder thread

18th

Vibration receiving chamber

19th

Pumping chamber

20th

Ring sealing membrane

21

drilling

22

Cylinder bore

23

Actuator

24th

Guide cylinder

25th

Spring element

26

Pumping chamber

27

Blind hole

28

drilling

29

Piston rod

30th

Bellows

31

End stop

32

attack

33

piston

34

Piston rod

35

Ring chamber

36

Cylinder bore

37

Valve

38

Pump membrane

39

Bellows

40

Piston rod

41

Pump room)

42

Valve

43

Spring element

44

Connecting channel

45

Metal strainer

46

Pressure equalization room

Claims (7)

1. Electro-hydraulic pump and drive element in a rotationally symmetrical housing made of metal, non-ferromagnetic metals, ceramic, plastic or composite materials or their combinations, characterized in that the piston rod ( 2 ) more than one pump chamber ( 19 ) through the respective ring membrane ( 4 ), the ring sealing membrane ( 20 ), the ring web ( 5 ) and one or more radially symmetrical bores ( 21 ) is formed, connected in series and in flow connection with the respective piston rod bore ( 16 ), the final ring membrane being the spring plate membrane ( 6 ) forms, or that the piston rod bore ( 16 ) is designed as a blind hole ( 27 ) and the pumping chamber ( 26 ) and all others are filled to the full with hydraulic oil and via the bellows ( 30 , 39 ) or the piston ( 33 ) acts on the control element ( 23 ) or the pump membrane ( 38 ) in the sense of a hydraulic transformation, wobe i the annular chamber ( 35 ) is also completely or partially filled with hydraulic oil and is sealed with the guide cylinder ( 24 ). 2. Electro-hydraulic pump and drive element according to claim 1, characterized in that the abutment piston ( 7 ) in the cylinder ( 8 ) slides or does not touch its wall. 3. Electro-hydraulic pump and drive element according to claim 1 and 2, characterized in that the bellows ( 30 , 39 ) with the piston rod ( 29 , 40 ) and the position element ( 23 ) or the pump membrane ( 38 ) positively or non-positively connected is. 4. Electro-hydraulic pump and drive element according to one of claims 1 to 3, characterized in that the bellows ( 39 ) is omitted and the remaining space is filled with hydraulic oil. 5, electrohydraulic pump and drive element according to one of claims 1 to 4, characterized in that the ring web ( 5 ) and all others without an annular sealing membrane ( 20 ) surround the piston rod ( 2 ) in a sliding seal with or without an annular seal. 6. Electro-hydraulic pump and drive element according to one of claims 1 to 5, characterized in that the valves ( 1 , 11 ) at the respective ends of the piston rod ( 2 ) are integrated into this. 7. Electro-hydraulic pump and drive element according to one of claims 1 to 6, characterized in that the blind hole ( 27 ) via the connecting channel ( 44 ) and the non-positively or positively inserted metal sieve ( 45 ) is connected to the pressure compensation chamber ( 46 ) , wherein this is filled with a one-piece or multi-piece or open-pore material with a negative temperature coefficient, each of which is completely flushed with hy draulic oil or that the metal sieve ( 45 ) is replaced by a follower piston provided with an annular seal, the pressure compensation chamber ( 46 ) then contains no hydraulic oil.