EP0886036B1 - Compressed air piston motor - Google Patents

Abstract

The piston (4) inside the cylinder reciprocates and connects to the piston rod (41) which feeds axially from the cylinder head (2) or from the cylinder floor (3). To facilitate supply and exhaust of the compressed air into or out of the cylinder (1) there is both an inlet and an outlet. The slide valve gear (8) is fixed to a piston which moves within a control cylinder. The cylinder contains control openings which provide a supply and exhaust connection for compressed air control of the piston.

Description

The invention relates to a compressed air piston engine, in particular for paint spraying devices, Dosing pumps, grease guns and the like, with one in one Piston cylinder by means of compressed air on its two piston surfaces a slide control alternately acted upon and thereby oscillating Movable working piston with a piston rod that is axially in one Cylinder head and / or a cylinder bottom is guided, in which for the Compressed air inflow or outflow into / out of the piston cylinder each have an inlet / outlet is provided, the slide control one in a control cylinder Movable control piston and control openings in the control cylinder are provided, each a supply / discharge or ventilation lines Connect the compressed air to the control cylinder and are influenced by the control piston and the slide control provided in / on the cylinder head or in / on the cylinder bottom and so is that the axes of the control piston and the working piston are approximately perpendicular stand on each other, with the cylinder head and the cylinder bottom each have a switching valve for the compressed air from the working piston can be actuated and switches the slide control, the switch valves one protruding into the piston cylinder from the working piston of the Compressed air piston engine have operable valve piston rod.

Such a, usually single-acting, compressed-air piston engine already exists known and can also be designed double-acting without much effort, where an implement is connected to each end of the pneumatic piston engine is. The piston cylinder with the cylinder head or Be formed in one piece, but it is more advantageous if both the cylinder head as well as the cylinder bottom of the piston cylinder made separately and the parts assembled afterwards, like that for example in the patent DE 33 42 388 C3, so that the required Machining of the parts can be kept low.

Regardless of such air piston engines are for Reversal of the linear movement of the working piston required outside the slide controls provided for the piston cylinder that the axes of the associated control piston and the control cylinder run parallel to the axis of the working piston.

The slide control is either attached to the side of the piston cylinder and optionally carried out in one piece with it, or it is located as in the arrangement according to DE 33 42 388 C3 above the cylinder head or if necessary also below the cylinder bottom; in these Components, the slide control can be structurally integrated. Both orders are unfavorable.

In the former case, it is not possible to use the working stroke of the working piston without changing at the same time the entire slide control has to be replaced, each only for a certain stroke and thus designed for a certain height of the piston cylinder is. As very different for the different applications Working strokes are required at the manufacturer of such a compressed air piston engine many different sized slide controls be kept in stock; an adjustment of the working stroke is not or only very cumbersome for the user possible.

In the second case, the overall length of the air piston engine considerably through the slide control alone enlarged because if the control piston is kept shorter can be considered the working piston, so required he nevertheless a considerable one in the axial direction of both pistons additional space leading to the indispensable Space requirement of the working piston is added.

It is also already known to reverse the working piston through the changeover valves mentioned at the beginning to initiate, each with the valve piston rod a valve piston against the force of one Return spring shifts when it is off the working piston in its working direction on the last piece his working stroke is taken away; after reversing of the working stroke, the return spring conveys the Valve piston including the valve piston rod back to its previous position.

The invention has for its object the above Disadvantages of the known compressed air piston motors described of the type specified at the beginning to eliminate and a slide control space-saving and suitable for different working strokes of the working piston to install. In addition, it is another object of the invention the required fittings in such a compressed air piston engine easy to design and limited to a few components.

According to the invention the object with the features of claim 1 solved, each of the changeover valves provided with a differential slide is that of a first valve piston of larger and a second Valve piston of smaller piston area, which is at a fixed distance are attached to the valve piston rod.

The change in the working stroke of a compressed air piston engine designed in this way draws - essentially - only a corresponding change the piston cylinder, which is easy to change. It is remarkable that this advantage does not require additional compressed air guides, such as at all, in comparison with the known arrangements, rather less than more components have to be used and in particular the essential namely cylinder head and base, of the overall length of the piston cylinder are trained independently.

It is particularly useful if the axis of the control piston of the axis of the working piston is spaced because then the piston rod be stored at both ends and / or both through the cylinder head as well as can be passed through the cylinder base without doing so to be hindered by the slide control.

A preferred embodiment of such a compressed air piston engine according to the invention consists in that in the valve housing from a branch line air pressure the differential slide in a first end position moves in the valve piston rod partially into the piston cylinder protrudes. The differential slide is in constant contact with the upcoming air pressure in a preferred first end position from which he solely under the action of the working piston on its valve piston rod a second end position is movable - against that on the differential piston acting force from air pressure. In this way, a return spring be completely dispensed with, if only care is taken to ensure that the piston surfaces of the differential piston are continuously exposed to compressed air.

In particular, it is particularly useful if the switch valve is provided axially parallel to the working piston and in the cylinder head or bottom a circular cylindrical bushing for mounting the differential slide is provided, the implementation against preferably the piston cylinder by means of a elastic closure is blocked by the Valve piston rod is pierced and on which the first Valve piston can be applied under the effect of compressed air which is therefore somewhat cushioned there, so that noise and wear remain low. On the other hand, on their opposite this barrier Side, the implementation advantageously has one threaded bush locked with a screw plug in which the second valve piston is guided which is a supply / discharge line leading into the changeover valve shuts off as long as the first valve piston is on the closure rests. This ensures that the differential slide is independent of that in the Incoming / outgoing air pressure in the first end position as long as it is not from the piston is moved out of this.

Such an operation of the changeover valves in connection with the working piston is guaranteed if at least one control opening each in the control cylinder for the supply / discharge lines from the changeover valves, one Main line from the compressed air source and a ventilation line from the compressed air piston engine into the environment are provided if continue through work lines inlets / outlets connected to the slide control for the compressed air in the piston cylinder on both sides of the working piston from one of the changeover valves can be controlled by a Branch line via the main line with the compressed air source is connected and one of the supply / discharge lines affects the control cylinder when the control piston by alternating these feed / discharge lines flowing compressed air can be moved axially oscillating is when control chambers finally on the control piston are provided which are the control openings so influence that the main line alternately with an inlet / outlet and at the same time an outlet with the Environment is connected, and when finally the branch lines branched off from the main line so that it cannot be shut off are. The control chambers are expediently designed such that that the compressed air source always with the main line one of the inlets / outlets is connected to the flow.

In a simple way, compressed air connections between the cylinder head and the cylinder base by fixed Pieces of pipe are made in a suitable manner, between clamped two, connecting their compressed air ducts; they must be replaced together with the piston cylinder if the working stroke is changed. It is useful, for example, if each one of the branch lines, one of the working lines for the inlets / outlets and / or the inlet / outlet of one of the Changeover valves with the slide control via a between the cylinder head and the cylinder bottom outside of the piston cylinder clamped pipe section become.

In particular, it is still appropriate if the Control cylinder closed on the front side by locking pieces is so that it is in the cylinder head / bottom continuous bore can be formed; the locking pieces are best threaded plugs. If on that Control piston preferably elastic stops at the end are provided, which alternately on the closure pieces stop, then the control piston even spared; the elastic design of the stops extends the life of the spool and reduces noise.

The supply / discharge lines from the changeover valves open into close the locking pieces so that they are off the spool cannot be influenced and this alternately the air pressure of the Compressed air source is exposed.

A particularly simple construction of the control piston occurs when there is a second control chamber on each provided on both sides of the first control chamber and alternately fluidly connected to an associated outlet is.

Overall, the structural simplification of the invention Air piston engine and its low Space requirements are a remarkable improvement its maintenance-free life has been achieved because the otherwise required return springs the usually high working frequency of the compressed air piston engine and its changeover valves and that related high dynamic load often fail due to spring breakage and be replaced have to. The reversal times for the working piston are very short because the differential slide through the permanent air pressure is always full Switching force are exposed.

Fig.1

einen erfindungsgemäßen Druckluft-Kolbenmotor in einem im wesentlichen mittigen Längsschnitt in einer Gebrauchslage,

Fig.2

eine Seitenansicht zu Fig.1 entsprechend einem Schnitt A-A aus Fig.1,

Fig.3

eine etwas vergrößerte Draufsicht zu Fig.2 entsprechend einem Schnitt B-B aus Fig.2,

Fig.4

eine ebenfalls etwas vergrößerte Draufsicht zu Fig.2 entsprechend einem Schnitt C-C aus Fig.2 und

Fig.5

eine Einzelheit D aus Fig.1, noch weiter vergrößert,

sämtlich schematisch vereinfacht dargestellt.The invention is explained below with reference to the drawing using an exemplary embodiment. Show it

Fig.1

an air piston engine according to the invention in a substantially central longitudinal section in a position of use,

Fig.2

2 shows a side view of FIG. 1 corresponding to a section AA from FIG. 1,

Figure 3

2 shows a somewhat enlarged top view corresponding to a section BB from FIG. 2,

Figure 4

a somewhat enlarged plan view of Figure 2 corresponding to a section CC of Figure 2 and

Figure 5

a detail D from Figure 1, further enlarged,

all shown schematically simplified.

A pneumatic piston engine according to the invention according to Fig.1 essentially from a piston cylinder 1, a cylinder head 2, a cylinder base 3 and a working piston 4 and the required Control devices and compressed air lines.

The tubular piston cylinder 1 is between the circular disc-shaped cylinder head 2 and the like shaped cylinder base 3 clamped and is on this by means of a concentric flanged disc 21.31 centrically arrested, facing each other first End faces 22,32 of the cylinder head 2 and the cylinder bottom 3 each provided in one piece with these are. A tubular air filter 5 is fitted into a Ring groove 23 on the other (second) end face 24 of the cylinder head 2 is inserted and on the other hand closed by a filter cover 51. Three Tensioning screws 6 clamp the filter cover 51 with the Air filter 5, the cylinder head 2, the piston cylinder 1 and the cylinder bottom 3 with each other so that the Air filter 5 and the piston cylinder 1 taut become. 1, 2 is a clamping screw 6 indicated in Figure 3 is the orientation of all three clamping screws 6 can be seen.

1 shows the longitudinal section in the region of the cylinder head 2, deviating from the other (axial) section, also been put through a changeover valve 7, that is also provided in the cylinder base 3 in the same way and is drawn enlarged in FIG. Both switch valves 7, whose spaced from a major axis HA of the air piston engine Location emerges from Fig. 3,4, are executed essentially the same and in a circular cylindrical, partly smooth and partly threaded Implementation 25,33 of the cylinder head 2 or the cylinder bottom 3 is provided. The bushings 25, 33 are on the one hand via an associated one Branch line ZL1.2 connected to a main line HL for the compressed air, which in turn from one omitted in the drawing and only by a directional arrow Q illustrated compressed air source fed with compressed air becomes; the arrangement is such that the compressed air is constantly in the Implementations 25.33 is due. The branch line ZL2 bridges outside of the piston cylinder 1 the free space between the cylinder head 2 and the cylinder base 3 with the help of a straight pipe section RS3, which axially parallel to the piston cylinder 1, clamped between the two.

Both switch valves 7 working as sliders are in turn axially parallel arranged to the piston cylinder 1 and have a differential slide 71, which consists of a first valve piston 71a larger and a second Valve piston 71b of smaller diameter, which is at a distance a firmly attached to each other on a common valve piston rod 71c are and the two alternate end positions in 1.5 are indicated, where the first end position is extended and the second are drawn with dashed lines. The bushings are 25.33 from the piston chamber 10 of the piston cylinder 1 by an elastic closure 72 pneumatically separated, that in the cylinder head 2 or the cylinder bottom 3 is fastened and has a guide bore 72a in which the Valve piston rod 71c is axially movable. You can in the piston chamber 10 protrude so that then its free end face 71d is in the working area of the working piston 4.

Furthermore, the bushings 25, 33 from the surrounding area U are one Locking screw 73 with a central vent hole 73a separated. An aligned threaded bushing 74 is located on the screw plug 73 a guide cylinder 74a in which the second, smaller valve piston 71b is easily guided longitudinally. One ends in the guide cylinder 74a Inlet / outlet Z1.2 to a slide control located in the cylinder head 2 8. The first, larger valve piston 71a, however, is directly on the smooth cylindrical surface of the bushing 25.33. During the feed / discharge Z1 opens directly into the slide control 8, bridges at the supply / discharge line Z2 from the cylinder base 3 a straight (third) pipe section RS1 the free space between the cylinder head 2 and the cylinder bottom 3, clamped between the two.

In Fig.1 is also indicated that the working piston 4 with a piston rod 41 is provided in the cylinder head 2 and the cylinder bottom 3 is mounted centrally and slightly longitudinally. At its (bottom) end an implement can be coupled; for double-acting devices this is possible at both ends.

According to FIG. 2, piston chamber 10 is located on both sides of the working piston 4 each a combined inlet / outlet 26,34 for the compressed air in the Cylinder head 2 and the cylinder bottom 3. The inlets / outlets 26, 34 are by means of Working lines AL1.2 pneumatically connected to the slide control 8, the working line AL2 via a (second) straight pipe section RS2 the free space between the cylinder head 2 and the cylinder bottom 3, clamped between the two, bridged. directional arrows R1 (Fig.2) indicate the oscillating exposure of the working piston 4.

In Fig.4 all pipe pieces are RS1-3 and theirs spatial arrangement well recognizable.

The slide control 8 is best in Fig.3 too recognize in which they are shown cut in the middle is. In one in the form of a socket in the cylinder head 2 inserted control cylinder 81 is a control piston 82 guided axially easily movable. The control cylinder 81 extends transversely to the main axis HA of the Air piston engine and (Fig.1) of this around the dimension e spaced in such a way that the piston rod 41 is not affected in its axial position. Lock two threaded plugs as locking pieces 83 the control cylinder 81 in the direction of its control axis SA (Fig.2). Is on the end faces of the control piston 82 each have an elastic stop 84 attached to the the movement of the control piston 82 to the adjacent one Closure piece 83 resiliently meets.

The supply / discharge lines open in the vicinity of the closure pieces 83 Z1.2 from the changeover valves 7 so that they, not lockable, always have an associated face of the control piston 82 alternately apply compressed air can. During the working piston 4 and the two valve pistons 71a, 71b each with only one piston ring are equipped on their lateral surfaces in the slide control 8 a total of five against each other areas to be sealed by four located on the control piston 82 and approximately the same Piston rings arranged at axial distances from one another pneumatically in corresponding annular grooves 82a are separated. Between the sealing piston rings are on the outer surface of the control piston 82 annular control chambers 82b, c recessed, which two adjacent control openings 81a-c with each other flow connections in which the main line HL, the working lines AL1.2 and ventilation lines EL lead; the vent lines EL lead on the other hand indicated in the environment U via the air filter 5 by arrows R2 (Fig.2).

The arrangement works without difficulty readable from the drawing.

The differential slide 71 are under the influence of the constant pending via the branch lines ZL1,2 Air pressure from the main line HL so long with your first valve piston 71a on the respective closure 72 at how the associated, overly in the piston chamber 10 projecting valve piston rod 71c not from the working piston 4 is charged. In this first, undressed drawn end position of the differential slide 71 are the respective feed / discharge lines Z1.2 from the associated ones Branch lines ZL1.2 separated and vented via the vent holes 73a.

The working piston 4 transports the differential slide 71 into the dashed second end position, then compressed air gets into the supply / discharge lines Z1.2, so that the spool 82 axially into its other End position comes, and the vent holes 73a are cordoned off. The supply / discharge lines Z1.2, accordingly in the first end position of the differential slide 71 act as venting discharges, end on both sides of the control piston 82 and cannot be influenced by this in the control cylinder 81 (Fig.3).

The control piston 82 connects to its first control chamber 82b, as indicated in Figure 3, with the Main line HL related control opening 81a one of the control openings 81b, in which one of the working lines AL1.2 opens. The control chamber 82b is consequently always flowing. Connects at the same time one of the second control chambers 82c the other control opening 81b with one of the control openings 81c, in which the vent lines EL open while the respective other second control chamber 82c is ineffective and interrupts any air flow.

In this way, the working piston 4 from his End position moves, and the slide control 8 reversed as soon as the free in the piston chamber 10th projecting valve piston rod 71c is reached; the associated changeover valve 7 then controls the Slider control 8 again.

reference numeral

1

Piston Cylinder

10

piston chamber

2

cylinder head

21

shoulder washer

22

first face

23

ring groove

24

second face

25

execution

26

Inlet / outlet

3

cylinder base

31

shoulder washer

32

first face

33

execution

34

Inlet / outlet

4

working piston

41

piston rod

5

air filter

51

filter cover

6

clamping screw

7

switching valve

71

differential slide

71a

first valve piston

71b

second valve piston

71c

Valve piston rod

71d

free face

72

shutter

72a

guide bore

73

Screw

73a

vent hole

74

threaded bushing

74a

transfer cylinder

8th

slider control

81

control cylinder

81a-c

control port

82

spool

82a

ring groove

82b, c

control chamber

83

closing piece

84

attack

a

distance

e

measure

AL1,2

working line

EL

Outlet, vent line

HA

Axis, main axis

HL

main

Q

Direction arrow, compressed air source

R1,2

arrow

RS1-3

pipe section

SA

Axis, control axis

U

Surroundings

Z1,2

Supply / discharge

ZL1,2

branch line

Claims (15)

1. Compressed-air piston motor, in particular for paint-spraying devices, dosing pumps, grease guns and the like, having a working piston (4) which is movable, alternately acted upon by compressed air at its two piston surfaces by means of a slide control (8) and thereby in oscillating fashion, in a piston cylinder (1) and has a piston rod (41) which is axially guided in a cylinder head (2) and/or a cylinder bottom (3), in each of which there is provided an inlet/outlet (26) for the compressed-air inflow or outflow into/out of the piston cylinder (1), the slide control (8) having a control piston (82) movable in a control cylinder (81) and there being provided in the control cylinder (81) control openings (81a-c) which each fluidically connect a supply/discharge line (Z1,2) for the compressed air to the control cylinder (81) and are influenced by the control piston (82), and the slide control (8) being provided in/on the cylinder head (2) or in/on the cylinder bottom (3) and such that the axes (SA,HA) of the control piston (82) and of the working piston (4) are approximately perpendicular to each other, the cylinder head (2) and the cylinder bottom (3) each having a switch valve (7) for the compressed air, which is actuable by the working piston (4) and switches the slide control (8), the switch valves (7) having a valve piston rod (71c) which projects into the piston cylinder (1) and is actuable by the working piston (4) of the compressed-air piston motor,
   characterised in that
   each of the switch valves (7) is provided with a differential slide (71) consisting of a first valve piston (71a) of larger piston area and a second valve piston (71b) of smaller piston area, which are fastened at a fixed distance (a) on the valve piston rod (71c).
2. Compressed-air piston motor according to Claim 1,
   characterised in that the axis (SA) of the control piston (82) is spaced from the axis (HA) of the working piston (4).
3. Compressed-air piston motor according to Claim 1 or 2,
   characterised in that the valve pistons (71a, b) are fastened on the valve piston rod (71c) in such a way that the air pressure present in the valve housing from a branch line (ZL1,2) moves the differential slide (71) into a first end position, in which its valve piston rod (71c) partially projects into the piston cylinder (1).
4. Compressed-air piston motor according to Claim 3,
   characterised in that the switch valve (7) is provided with its axis parallel to the working piston (4), and a circular-cylindrical passage (25,33) for mounting the differential slide (71) is provided in the cylinder head (2) and the cylinder bottom (3).
5. Compressed-air piston motor according to Claim 4,
   characterised in that the passage (25,33) is blocked off from the piston cylinder (1) by means of a preferably elastic plug (72) which is penetrated by the valve piston rod (71c) and against which the first valve piston (71a) can be laid under the action of the compressed air.
6. Compressed-air piston motor according to Claim 5,
   characterised in that the passage (25,33) has at the other side a threaded bushing (74) which is fixed by means of a screw plug (73) and in which the second valve piston (71b) is guided, which blocks off a supply/discharge line (Z1,2) leading into the switch valve (7) as long as the first valve piston (71a) lies against the plug (72).
7. Compressed-air piston motor according to one of Claims 1 to 6, characterised in that

   (a) at least one control opening (81a-c) each for the supply/discharge lines (Z1,2) from the switch valves (7), a main line (HL) from the compressed-air source (Q) and vent lines (EL) from the compressed-air piston motor into the environment (U) are provided in the control cylinder (81),

   (b) inlets/outlets (26,34), connected by working lines (AL1,2) to the slide control (8), for the compressed air in the piston cylinder (1) are controlled on both sides of the working piston (4) each by one of the switch valves (7), which is connected to the compressed-air source (Q) by a branch line (ZL1,2) via the main line (HL) and influences one of the supply/discharge lines (Z1,2) to the control cylinder (81),

   (c) the control piston (82) is movable in axially oscillating fashion by the compressed air alternately flowing via these supply/discharge lines (Z1,2),

   (d) control chambers (82b,c) are provided on the control piston (82), which influence the control openings (81a-c) such that the main line (HL) is alternately connected to an inlet/outlet (26,34) and at the same time an outlet (EL) is connected to the environment (U), and

   (e) the branch lines (ZL1,2) from the main line (HL) are branched off in a way that they are unable to be blocked off.
8. Compressed-air piston motor according to Claim 7,
   characterised in that the control chambers (82b,c) are designed such that the compressed-air source (Q) is always fluidically connected to one of the inlets/outlets via the main line (HL).
9. Compressed-air piston motor according to one of Claims 7 and 8, characterised in that one of the branch lines (ZL2) is guided via a first pipe section (RS1) clamped between the cylinder head (2) and the cylinder bottom (3), outside the piston cylinder (1).
10. Compressed-air piston motor according to one of Claims 7 to 9, characterised in that one of the working lines (AL1,2) for the inlets/outlets (26) is guided via a second pipe section (RS2) clamped between the cylinder head (2) and the cylinder bottom (3), outside the piston cylinder (1).
11. Compressed-air piston motor according to one of Claims 7 to 10, characterised in that the supply/discharge line (Z2) of one of the switch valves (7) is connected to the slide control (8) via a third pipe section (RS3) clamped between the cylinder head (2) and the cylinder bottom (3) outside the piston cylinder (1).
12. Compressed-air piston motor according to one of Claims 1 to 11, characterised in that the control cylinder (81) is closed at its ends by sealing parts (83).
13. Compressed-air piston motor according to Claim 12,
    characterised in that preferably elastic stops (84) which alternately strike the sealing parts (83) are provided at the ends of the control piston (82).
14. Compressed-air piston motor according to one of Claims 1 to 13, characterised in that the supply/discharge lines (Z1,2) from the switch valves (7) open out in the vicinity of the sealing parts (83) such that they cannot be influenced by the control piston (82).
15. Compressed-air piston motor according to one of Claims 1 to 14, characterised in that one second control chamber (82c) each is provided on the control piston (82) on both sides of the first control chamber (82b) and is alternately fluidically connected to an associated outlet (EL).

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