WO2003023191A1 - Parallel rotating piston engine with side walls - Google Patents

Abstract

The invention relates to a piston engine comprising a housing (l, 3, 4, 5) and a piston (8) which is mounted on the crank pin (7) of a crankshaft (2) and performs a parallel rotation movement around said crank pin whilst being secured against angle variations. Said piston forms a chamber (13) with an outer wall which is formed on a plane which is perpendicular to the axis of the crankshaft and which is concave (9) and convex (10) in sections thereof in relation to a peripheral wall which is formed by the housing and which is concave (11) and convex (12) in sections thereof; said chamber (13) opening and closing during said parallel rotation and having a modifiable volume in addition to being defined by side walls (14) which are disposed at an axial distance therefrom. The invention is characterized in that one of the side walls (14) is secured to the piston (8) and slidingly overlaps with an end wall (3') of the chamber part (3) of the housing (l, 3, 4, 5) forming the peripheral wall (11, 12) which is perpendicular to the axis, and slidingly overlaps with an end wall (8') of the piston (8) which is perpendicular to the axis.

Description

 Parallel rotating piston machine with side walls

The invention relates to a piston machine of the type mentioned in the preamble of claim 1.

A generic piston machine is known from WO 93/25801. As stated there, it can be used as an expansion or compression machine, pump or e.g. can also be used as an internal combustion engine with one or more chambers.

In the known construction, the end face sealing of the piston end faces in the axial direction of the crankshaft takes place with respect to two parallel side walls of the chamber, which are formed by the housing. However, this design has disadvantages.

If the piston machine is used as an internal combustion engine or as a compressor, considerable amounts of heat are generated in the chamber, which, among other things, must also be dissipated by the piston and subject it to high thermal loads. In particular, the crankshaft and its bearings are thermally stressed. Heat dissipation from the piston presents a significant problem, which is exacerbated by the fact that the piston is trapped between the fixed side walls. From DE 37 16 017 AI and US 1378065 similar parallel rotating piston machines are known, in which the pistons do not run on fixed side walls, as in the known construction mentioned above, but in which side surfaces attached to the piston, which run with it, seal on fixed housing parts to run. This has the advantage that the piston is no longer thermally locked between fixed side walls. Rather, the moving side walls serve as moving cooling surfaces that cool the piston well. This reduces thermal loads on the piston and the crankshaft bearings.

A disadvantage of these two constructions with side walls attached to the piston and running with them is the fact that both side walls are rigidly connected to one another via the piston. There is therefore a risk of pinching if the side walls are thermally deformed.

The object of the present invention is to reduce the thermal problems in a generic piston machine while avoiding the risk of pinching.

This object is achieved with the features of claim 1.

According to the invention, the piston runs on one side on a fixed side wall and has a moving side wall on the other side. The main advantages of the second-mentioned constructions, namely the good cooling of the piston by the moving side wall, result. The risk of pinching of these known constructions is avoided, however, since a moving side wall is only provided on one side of the piston. The piston can thus move laterally with its moving side wall opposite the fixed one Dodge the side wall, so that jamming between the side walls is avoided in the event of thermal deformation. Another advantage of this construction is that the machine according to the invention can be designed with this construction non-destructively for those cases in which a gas is normally to be compressed, but under certain circumstances an incompressible liquid can also be sucked in. Then attempting to compress the liquid would destroy the machine. However, if the piston and chamber part, each with side walls attached to them, can dodge laterally, z. B. the piston can dodge a return spring, such destruction is prevented.

The features of claim 2 are advantageously provided, this embodiment has design and assembly advantages.

The piston is advantageously mounted adjustable in the axial direction relative to the chamber part. The piston can thus be moved axially from a position with a sliding overlap of the side walls into a position in which the side walls overlap with a gap. This gap can be enlarged or reduced. A targeted leakage of the chamber of the piston machine can thus be set. This is of advantage, for example, when used as a compressor. A large gap, that is to say a large leak, can be set in the course of running or when running up, so that the force absorption when idling is reduced. The air flowing through the gaps thus created also provides additional cooling.

In such an embodiment, it can also be advantageously achieved according to claim 4 by arranging both the outer wall of the piston and the circumferential wall of the chamber part at an oblique angle, which when the piston is axially displaced relative to the chamber part by parallel adjustment. the inclined surfaces the distance between them is changed. If the helix angle is very small, the distance between the outer wall of the piston and the peripheral wall of the chamber part can be adjusted very finely with axial adjustment of the piston. The gap between the outer wall and the peripheral wall can thus be adjusted very finely on the lines on which they run on one another. This enables manufacturing inaccuracies and, for example, thermal expansion to be compensated for, and a very narrow line gap to be set, which nevertheless avoids touching the surfaces.

The features of claim 5 are advantageously provided. If the side walls overlap with an elastic seal, the piston can be adjusted slightly in the axial direction with respect to the chamber part without any lateral leaks occurring, since these are compensated for by the elastic seal. The gap at the line of contact between the peripheral wall and the outer wall can thus be adjusted without the chamber leaking.

The features of claim 6 are advantageously provided. In this embodiment, if the setting is too narrow, there will be contact between the peripheral wall and the outer wall in the vicinity of the edge of the two inclined surfaces, which lies on the side wall which is fastened to the chamber part, that is to say in the vicinity of the stationary side wall. This enables the targeted attachment of a touch sensor near this side wall, e.g. B. in the peripheral wall of the chamber part. The distance to the outer wall of the piston can be measured with this sensor. If this distance becomes too small, the axial adjustment of the piston can be corrected accordingly. Such a sensor should preferably be arranged at the hottest point on the wall, ie in the vicinity of the outlet valve. The invention is shown schematically, for example, in the drawings. Show it:

1 shows an axial view of a piston machine according to the invention in the section along the line 1 - 1 in FIG. 2,

Figure 2: an axial section along line 2 - 2 in Figure 1 and

Figure 3: in section corresponding to Figure 2, another embodiment of the piston machine.

As shown in FIGS. 1 and 2, the piston machine shown has a housing consisting of a crank bearing block 1 with two crankshafts 2 mounted therein and a chamber part 3 which is rigidly connected to the crank bearing block 1 via housing parts 4 and 5.

The crankshafts 2 each form crank pins 7 which are attached via crankings 6 and are mounted in a piston 8. When the axes of the crank pins 7 revolve, as shown with dashed arrows in FIG. 1, the two crankshafts revolving in an angle-synchronous manner, the parallel rotation mentioned in WO 93/25801 results. For details of the basic concept of this piston machine, reference is made to the document mentioned. To force the angular synchronism of the two crankshafts 2, these can be synchronized via a synchronous gear (not shown). For better stability of the piston in its parallel rotation and to avoid a synchronous transmission between the crankshafts, more than two crankshafts can be provided. Of the several crankshafts provided, one can be used for drive or output, while the other idle only serve to force the parallel rotation. As FIG. 2 shows, both the piston 8 and the chamber part 3 of the housing have the same length in the direction of the axis of the crankshaft 2 with end walls 8 'of the piston 8 and 3' of the chamber part 3 which are in alignment with one another.

The piston 8 forms convex and concave wall surfaces 9, 10 on its outer wall lying towards the chamber part 3. The chamber part 3 forms concave and convex wall surfaces 11 on its peripheral wall lying towards the piston,

12 out. When the piston 8 rotates in parallel, the wall surfaces 9, 10 slide smoothly on the wall surfaces 11, 12 and form a chamber 13 which, when viewed in the axial direction, is closed at the end with parallel side walls 14, 14 '.

The side walls 14, 14 'are fastened to the piston 8 and overlap the end faces 3' of the chamber part 3, on which they slide flat during the parallel rotation of the piston 8 and seal the chamber 13.

The side walls 14, 14 'can be formed in one piece with the piston 8. In the illustrated embodiment, as shown in particular in FIG. 2, they are designed as separate flat plates which are placed against the end faces 8 'of the piston 8 and are connected to the latter by means of screws 15.

When the piston 8 rotates in parallel with the crank pin 7 rotating clockwise according to FIG. 1, the chamber closes in the rotational position shown

13 just at point 16 between the wall parts 9 and 11 and at the other end at point 18 between the wall parts 10 and 12. With further rotation of the piston 8, the wall parts 9 and 11, advantageously sealing against each other with a small gap, run off each other, likewise the Wall parts 10 and 12. The chamber 13 shrinks continuously to about point 19, in which an outlet channel 20 is provided with a check valve 21 opening outwards. The illustrated The machine can be used as a compressor, for example, which is driven by one of the crankshafts 2.

If after approximately 180 ° crankshaft rotation, compared to the position shown, the smallest volume of the chamber 13 is reached, the chamber opens when the crankshafts continue to rotate, so that at points 16 and 18 fresh air from both ends of the chamber for filling and cooling purposes can flow in.

The side walls 14, 14 'shown can be provided on their outside with cooling fins in order to effect better cooling of the piston.

The construction shown can be used with slight modifications for all the embodiments of the piston machine shown in WO 93/25801. The piston machine can be used for all of the applications mentioned in this document.

Figure 3 shows another embodiment of the piston machine shown in section corresponding to Figure 2. Wherever possible, the same reference numerals are used.

In this embodiment, the one side wall 14 is fastened to the piston 8 in the same way as in the embodiment in FIG. The other side wall 14 ', which lies towards the housing 4, is fastened to the chamber part 3 in a corresponding manner. The piston 8 can therefore be moved with its side wall 14 relative to the chamber part 3 and its side wall 14 'to the left in the axial direction of the crankshaft 2, that is to say away from the housing part 4, the side walls 14, 14' then being moved away from the end walls 8 'and 3'. with a gap. As a result, the chamber 13 opens outwards through the gaps thus created. In the embodiment of FIG. 3, piston 8 is shown somewhat out of phase with respect to the position shown in FIGS. 1 and 2. The crankshaft 2 has rotated about 90 ° relative to the position in FIG. 1, so that the line contact between the chamber surfaces 9 and 11 in FIG. 1 now lies essentially in the section line shown in FIG. At this point, the chamber 13 now forms a narrow line gap, enlarged in the figure for the drawing, with which the chamber 13 is sealed.

As FIG. 3 shows, both the outer wall of the piston 8 formed from the parts 9 and 10 and the peripheral wall of the chamber part 3 formed from the parts 11 and 12 are formed at oblique angles W1 and W2. Thus, by moving the piston 8 relative to the chamber part 3 in the axial direction of the crankshaft 2, the gap between the piston 8 and the chamber part 3 shown in FIG. 3 can be increased.

The helix angles W1 and W2 are preferably different, as shown in FIG. 3, in such a way that the angle W2 on the peripheral wall of the chamber part 3 is greater than the angle W1 which is formed by the outer wall of the piston. Therefore, the edges of the outer wall and the peripheral wall on the side of the side wall 14 'are closer together than the other edges on the side wall 14. If the peripheral wall and the outer wall come into contact, this occurs at the edges of the side wall 14'.

There sensors, not shown, for. B. be arranged in the peripheral wall of the chamber part 3, which measure the distance to the outer wall of the piston 8. The helix angles W1 of the outer wall of the piston 8 and W2 of the peripheral wall of the chamber part 3 are always arranged above them so that the outer wall and the peripheral wall are conical. So there are the wall parts 11 and 12 of the peripheral wall of the chamber part 3 and the wall parts 9 and 10 of the outer wall of the piston 8 each conical.

For targeted axial displacement of the piston 8 with respect to the chamber part 3, the piston 8 is supported on its side opposite the crankshaft 2 with an articulated arrangement 20 which e.g. as indicated in the exemplary embodiment, is formed from two thrust bearings which are concentric with the crank pin 7 on the one hand and with the crankshaft 2 on the other. This bearing arrangement 20 is mounted on a housing part 21 which is adjustable in the direction of the axis of the crankshaft 2 relative to its bearing block 1. The housing part 21 is displaceable in the direction of the axis of the crankshaft 2 with respect to the crank bearing block with a sliding guide 22 and is adjustable with a screw 23 which, as shown, is rotatably held in the housing part 21 and can be screwed into a projection 24 of the crank bearing block 1 with threaded engagement , When adjusting the screw 23, the piston 8 is tightened or released in the direction of the axis 2 against the crank bearing block 1. It does not need to be actively adjusted in the direction away from the crank bearing block 1, that is to say to the left in FIG. 3, since the pressure in the chamber 13 always pushes it in the direction to the left, ie away from the crank bearing block 1.

By adjusting the screw 23, the distance between the side walls 14 and 14 'can thus be adjusted, as a result of which the gap of the chamber 13 shown in FIG. 3 can be enlarged or reduced. As an alternative to the embodiment shown in FIG. 3, the piston 8 can also be held axially and the chamber part 3 can be adjusted in the axial direction relative to the housing 4, 5.

As an alternative to these embodiments, the side wall 14 can also be fastened to the chamber part 3 and the side wall 14 'to the piston 8. Then the piston would have to be adjusted to the right, that is to say in the direction of the housing part 4, for the axial adjustment.

Instead of the adjusting screw 23 shown in FIG. 3, a servomotor can be provided which, for. B. is actuated electrically by a suitable controller, depending on engine parameters such as the machine temperature, the speed and the like, for example to optimize the distance between the peripheral wall and the outer wall to compensate for thermal expansion or, for example, to move the piston 8 in the axial direction so far at idling speed that the side walls lift off. The mentioned distance sensor between the outer wall and the peripheral wall can be used to control this motor. Another sensor for controlling the servomotor can be provided, for example, between the piston 8 and the side wall 14 '.

So that the tightness of the chamber on the side walls 14 and 14 'is not interrupted, these are elastically sealed with line seals 25. The line seals 25 can be formed as grooves parallel to the substantially S-shaped edges of the piston 8 on the one hand and the chamber part 3 on the other hand, as shown in FIG. Elastic sealing material or resiliently sealed sealing strips can be arranged in the grooves, which sealingly absorb a certain adjustment path of the piston 8 by adjusting the screw 23. If the screw 23 is unscrewed even further, the piston 8 lifts too far in the direction to the left in FIG elastic seals 25 from the side walls 14 and 14 ', so that the chamber 13 is now opened to the outside, for example to reduce the force absorption when the machine is idling.

3, the sliding guide 22 between the piston 8 and the chamber part 3 can be provided with an additional overload protection in the form of a spring (not shown), which acts on the piston 8 when the pressures in the direction of the sliding guide in the chamber 13 are too high can escape sideways. Such evasive backup can be advantageous if, for. B. when compressing air is erroneously sucked in water that is not compressible and would thus lead to the destruction of the machine. In such a case, the piston could move sideways and the destruction could be prevented.

Claims

1. Piston machine with a housing (1, 3, 4, 5) and with a on the crank pin (7) of a crankshaft (2), secured against angular changes around this parallel rotating piston (8), which with a in the perpendicular to Crankshaft axis plane sectionally convex (9) and concave (10) formed outer wall compared to a peripheral wall formed by the housing, sectionally concave (11) and convex (12) formed a chamber (13) that opens, closes and changes in volume during parallel rotation is delimited by axially spaced side walls (14), characterized in that one of the side walls (14) is attached to the piston (8) and an end wall (3 ') of a chamber part forming the peripheral wall (11, 12) perpendicular to the axis (3) of the housing (1, 3, 4, 5) slidably overlaps while the other side wall (14 ') is attached to the chamber part (3) and an end wall (8') of the piston (8) perpendicular to the axis slidingly overlapped. 2. Piston machine according to claim 1, characterized in that the Piston (8) attached side wall (14) is designed as a flat plate attached to the end walls (3 ') of the piston (8). 3. Piston machine according to claim 1, characterized in that the Piston (8) relative to the chamber part (3) is mounted adjustable in the axial direction. 4. Piston machine according to claim 3, characterized in that the outer wall (9, 10) of the piston (8) and the peripheral wall (11, 12) of the chamber part (3) at an angle (Wl, W2) with respect to a parallel to the axis Line are conical. 5. Piston machine according to claim 4, characterized in that the Side walls (14, 14 ') are elastically sealed in their sliding overlap. 6. Piston machine according to claim 4, characterized in that the Angles (W1, W2) are so slightly different that the peripheral wall (11, 12) and the outer wall (9, 10) have a smaller distance at their edges from the side wall (14 ') attached to the chamber part (3) than at the edges opposite edges.