EP1009914A1

EP1009914A1 - Rotating piston machine

Info

Publication number: EP1009914A1
Application number: EP98941136A
Authority: EP
Inventors: Michael Rechberger
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-08-28
Filing date: 1998-08-27
Publication date: 2000-06-21
Anticipated expiration: 2018-08-27
Also published as: AT413423B; WO1999011907A1; EP1009914B1; ES2181259T3; ATA144697A; US6227832B1; DE59805027D1; JP2001515166A; AU8963898A

Abstract

In a rotating piston machine, a rotor rotates in a housing and slides that can be radially moved in the rotor form variable volume chambers between the housing and the rotor. An even number of slides is provided and diametrically opposed slides form a rigid unit. The invention is characterised in that the rotor is eccentrically arranged in the housing and in that the inner wall of the housing satisfies the following equation, expressed in polar co-ordinates with the centre in the rotor axis: r( psi ) = {a<2>b<2>/[a<2>cos<2>(l( psi + pi /2)) + b<2>sin<2>(l( psi + pi /2))]}<1/2>, in which b is the shortest distance between the rotor axis and the housing in the south pole (S), and a is defined by the formula a(d,b) = {[3(d/2)<4> - 2b<2>(d/2)<2>]/[2(d/2)<2> - b<2>}<1/2>, d being the length of the slide and l being defined by the formula l = 2/ pi arccos({[a<2>-(a<4>+b<4>-a<2>b<2>)<1/2>]/(a<2>-b<2>)}<1/2>).

Description

Rotary lobe machine

The invention relates to a rotary piston machine in which a rotor rotates in a housing and radially displaceable slides form variable-volume chambers between the housing and the rotor, an even number of slides being provided and diametrically opposed slides being combined to form a rigid unit are.

Such a rotary piston machine is known from GB 430 715 B. The housing has the shape of a Reuleaux triangle and the rotor is arranged centrally in this triangle. The advantage of such an arrangement compared to the use of one-sided, spring-loaded slide is that in the course of the rotation of the rotor, the housing walls only have to overcome the inertial mass of the slide for its reciprocating movement, while the centrifugal acceleration due to the combination of diametrically opposite slides is at least essentially canceled out and spring forces, as must always be provided in the case of individual slides in order to press the sliders against the housing wall, are eliminated at all.

A rotary lobe machine of the type mentioned at the outset is therefore subjected to significantly reduced wear compared to other rotary lobe machines with individually movable slides.

As further distant prior art, relating to these other rotary piston machines, reference can be made, for example, to DD-33 914 A, in which the housing has a circular cross section and the rotor arranged eccentrically in the housing also essentially has a circular shape, but with recesses, the in cross section are delimited by a circular arc section from which the rotor is cut out in order to increase the size of the chambers which form. The (four) slides are pressed by springs from the rotor outwards against the casing wall, which together with the centrifugal acceleration leads to high contact pressures and high wear.

Despite its advantages compared to the DD-A, it is disadvantageous in the rotary piston machine known from GB-B that the formation of three housing pockets is inevitable due to the mandatory shape of the Reuleaux triangle, each pocket having an expanding first when passing through a slide , then again forms a reducing chamber between the slides. In internal combustion engines, for example, this necessarily leads to the formation of 6-stroke systems with interposed cooling sections. Another disadvantage caused by this is that each slide is pushed back and forth radially three times in the course of one revolution, which in turn leads to relatively high acceleration peaks in the course of one revolution.

The invention aims to remedy this situation and to provide a rotary piston machine of the type defined in the introduction, in which each slide is only reciprocated once in the course of one revolution of the rotor.

According to the invention, this is achieved in that the rotor is arranged eccentrically in the housing, that the housing is symmetrical with respect to the connecting straight line between the axis of the rotor and the point of the housing closest to this axis, the south pole, and that on the basis of one through the axis of rotation of the rotor, normally on the axis of symmetry or in the direction of the axis of symmetry, the XY coordinate system and with polar coordinates [r, φ] with the center in the rotor axis and the angle φ = 0 lying in the direction of the positive X-axis, the inner wall of the housing fulfills the following equation:

r (φ) = {from ² / [a ² cos ² (l (φ + τι / 2)) + b ² sin ² (1 (φ + τι / 2))]} l / 2

where: b is the shortest distance between the rotor axis and the

Housing wall at the south pole is, a by the formula: a (d, b) = {[3 (d / 2) 4 - 2b ² (d / 2)] / [2 (d / 2) ² - b ² ]} l / 2 is given, where: d the length of the chords of the housing inner wall through the

The axis of rotation of the rotor, thus the radial extension of the slide, is and 1 by the formula

1 = 2 / τx arccos ({[a ² - (a4 + b4-a ² b ² ) l / 2] / (a ² -b ² )} l / 2) is given.

The choice of b and d, i.e. the shortest distance between the rotor axis and the inner wall of the housing on the one hand, and the radial extension of the slide on the other hand, completely determines the shape of the inner wall of the housing, since the curve is only in due to the requirement for symmetry with respect to the Y axis one quadrant must be specified and only one quadrant can be specified, the others result immediately.

In addition, there are boundary conditions: the horizontal (parallel to the X-axis) course at the south pole (which automatically follows from this at the north pole), the position of the housing inner wall at the intersection with the

X-axis at distance d, the demand for two, continuous differentiation in order to make the rotary-sliding movement of the sliders smooth, the monotonous growth of r (φ) in the fourth quadrant and the always non-negative curvature, which defines the curve.

Embodiments of the invention relate to the formation of the slide and their guidance in the rotot or along the housing.

In the drawing, some sections according to the invention through housings or rotors are shown schematically. 1 shows a housing shape with a = 1.5 and b = 1, FIG. 2 shows a housing shape with a = 2.0 and b = 1, and FIG. 3 shows a housing shape with a = 5 , 0 and b = 1, FIG. 4 shows a section through a turbine or fan, FIG. 5 shows a section through a 2-stage rotary piston internal combustion engine, FIG. 6 shows an axial section through a rotary piston internal combustion engine, FIG. 7 8 shows a section through a rotary piston internal combustion engine, FIG. 8 shows a slide in section, top view and side view, FIG. 9 shows a spring clip in front view, in top view and in side view, FIG. 10 shows a rotor in section and in side view, 11 shows an elliptical ring in top view and in side view, FIG. 12 shows a rotor segment in front view and in side view, FIG. 13 shows a segment seal in front view and in side view, FIG. 14 shows a rotor in section and in side view, FIG. 15 a rotor segment in front view and in side view and the Fi 16 shows a slide in front view, in side view and in top view. FIGS. 1 to 3 show different designs of housing shapes that can be used according to the invention depending on the ratio of parameters a and b. The coordinate systems used, the south pole S and the distances b and d are entered, where b is fixed at 1, since the shape of the curve depends only on the ratio a / b and thus also according to the above relationship a / d.

As can be seen directly from FIGS. 1 to 3, housing shapes according to the invention in the range from a / b = 2 can certainly be used technically, while at values of a / b which are substantially higher, strong accelerations of the slide occur when they are in the equatorial position ( parallel to the X-axis), whereby, in this position, there are also strong pressing forces from the housing wall and directed from the slide plane and therefore do not allow such shapes for technical use.

Useful ratios a / b are between 1.0 and 2.5, preferably between 1.25 and 2.0, where a and b have the meaning given above.

However, in the ratios shown in FIGS. 1 and 2, of course also in those in which a <1.5 or only slightly above 2, a rotary piston machine is created which does not have the disadvantages of the previously known machines and in particular by has favorable dynamic conditions for the movement of the slide in the radial direction within the rotor and also along the inner wall of the housing.

Fig. 4 shows a section normal to the axis of rotation of a turbine according to the invention or an inventive

Fan. Slides 1 move in the rotor 19 in oil, as will be explained in detail below. In the housing wall 32, which is only shown schematically in all representations, the suction opening 17 and the pressure opening 23 are shown schematically.

In an analogous reverse manner, however, it can also be used as a pump for generating a vacuum and for pumping liquids and as a compressor.

5 shows a section normal to the axis of rotation of a rotary piston internal combustion engine. An intake opening 17 of a compressor stage is shown schematically in the housing wall 32, furthermore an overflow duct 18 which leads from the pressure side of the compressor stage to the intake side of the engine stage and there an injection nozzle 20 is introduced in the area of the expansion chamber.

The slides 1 of the compressor stage are again guided in the oil in the rotor 19; for slides 21 of the rotor 22 in the combustion chamber, this is not possible for thermal reasons.

The processed combustion gases leave the rotary piston internal combustion engine at the exhaust opening 23. FIG. 6 shows a section through the parallel rotor axes of the two rotors 19, 22 of FIG. 5. In particular, the rounded corner design of the housing chamber can be seen from this figure. The bearings 29 for the rotors 19, 22 and the toothed wheels 31 which drive the compressor rotor 19 are entered.

Fig. 7 shows a section normal to the rotor axes of a rotary piston internal combustion engine. A pre-compressor outlet opening 26 opens into an expansion chamber 27, which ends in the discharge nozzle 28. The schematically drawn intake opening 17 and the overflow channel 18, which leads from the pre-compressor stage into the expansion stage, can also be seen. The guided in the compressor rotor 19 Sliders 1 are preferably again guided in the oil, while this is not possible in the case of the sliders in the rotor 22 which are thermally highly loaded by the combustion process.

FIG. 8 shows a slide 1 which is preferred according to the invention in section, in side view and in plan view, grooves 3 being visible, in which spring clips 4, one of which is shown in FIG. 9, can be used. In the slide 1, oil channels 2 are provided, which, due to the centrifugal acceleration, transport oil to the outside in the region of its axis of rotation, which is supplied to the rotor in which the slide 1 is used, and there the slide 1 or the spring clip 4 during its rotation lubricates and cools along the inside wall of the housing.

FIG. 9 shows a spring clip 4 which can be inserted into the grooves 3 of a slide 1 and which is provided with lubrication openings 5 from which the lubricating fluid can escape. The arrows indicate the direction of the (slight) elastic deformation due to the centrifugal acceleration, which improves the seal on the inner wall of the housing.

The webs 34 between the two ends of the slide 1 are offset in the individual sliders of a rotor by at least the web width, so that the individual sliders are arranged in the rotor so as to be radially movable past one another.

Fig. 10 shows a rotor for oil-lubricated slide 1, which is therefore not thermally high load, otherwise the oil will become blocked. Liquids other than 01 can also be used for lubrication, whereby both 01 and the other liquids can be used for cooling. In the case of vacuum pumps in particular, the slide can be cooled by liquids such as water and Lubrication is important, especially since the oil contamination can no longer be removed from the vacuum.

Such a rotor preferably consists of rotor segments 7, which are held together by rotor side walls 6. Ellipse rings 13 (FIG. 11) are inserted into grooves 8. The grooves 9 receive segment seals 15 (FIG. 13), the oil supply for the slide 1 or the spring clip 4 takes place through an inlet opening 10 in the rotor shaft.

11 shows an ellipse ring 13 in a side view and a top view. The direction of pressure is indicated by arrows. The ellipse ring 13 has an opening 16 for pressure and expansion compensation. The ellipse ring 13 serves to seal the slide 1 from the rotor. In the exemplary embodiment shown, two such ellipse rings are provided on each side of the rotor for each of the slide 1, thus four ellipse rings per slide.

A rotor segment in front and side view can be seen from FIG. 12, from which the grooves 8 for the elliptical rings 13 and the grooves 9 for the segment seal 15 (FIG. 13) can also be seen. The holes 14 are used to mount the side windows 6.

In Fig. 13 a segment seal 15 is shown in front and side view. This segment seal 15 seals the rotor from the side housing wall and is designed to be self-pressing.

Fig. 14 shows a thermally highly resilient rotor in axial section, a combustion chamber trough 26 being provided in each segment. A single rotor segment is shown in front and side view in FIG. 15, FIG. 16 shows an associated slide 21, which differs from the slide 1 due to the lack of oil supply and thus of the lubrication differs. Here too, the webs 34 are arranged as in the slide 1 (FIG. 8).

The method of operation of the rotary lobe machine according to the invention is the same as that of the conventional rotary lobe machines, except for the dynamic improvements in the slide movements and the special design of the slide, which is possible as a result, since the operation has not changed compared to the prior art.

Claims

Claims:

1. Rotary piston machine, in which at least one rotor (19, 22) rotates in a housing (32) and radially displaceable slides (1, 21) form variable-volume chambers between the housing and the rotor, an even number is provided by slides and diametrically opposite slides are combined to form a rigid unit, characterized in that the rotor is arranged eccentrically in the housing, that the housing with respect to the connecting straight line between the axis of the rotor and the point of the housing closest to this axis, the south pole (S), is symmetrical, and that on the basis of an XY coordinate system placed through the axis of rotation of the rotor, running normally on the axis of symmetry or in the direction of the axis of symmetry, and of polar coordinates [r, φ] with the center in the rotor axis and the Angle φ = 0 lying in the direction of the positive X axis, the inner wall of the housing (32) the following equation ng fulfilled:

r (φ) = (a ² b ² / [a ² cos ² (l (φ + τι / 2)) + b ² sin ² (1 (φ + τx / 2))]} l / 2

where: b is the shortest distance between the rotor axis and the

Housing wall at the south pole (S) is, a by the formula: a (d, b) = {[3 (d / 2) 4 - 2b (d / 2) ² ] / [2 (d / 2) ² - b ² ]} 1/2, where: d is the length of the chords of the housing inner wall through the

Axis of rotation of the rotor, thus the radial extension of the

Slider (1, 21), and 1 by the formula

2. Rotary piston machine according to claim 1, characterized in that the ratio a / b between 1.0 and 2.5, is preferably between 1.25 and 2.0, where a and b have the meaning given above.

3. Rotary piston machine according to one of claims 1 or 2, characterized in that its slide (1) have substantially radially extending oil channels (2) which with oil channels (5) in spring clips (4) which in grooves of the slide (1) sit and seal them against the inner wall of the housing, work together to reduce the friction between the inner wall of the housing and the slide.