WO2001036789A1

WO2001036789A1 - Rotating piston device

Info

Publication number: WO2001036789A1
Application number: PCT/EP2000/011066
Authority: WO
Inventors: Michael Kresin
Original assignee: Corporate Decision Gmbh
Priority date: 1999-11-12
Filing date: 2000-11-09
Publication date: 2001-05-25
Also published as: DE19954728A1

Abstract

The invention relates to a rotating piston device having a housing provided with a housing body (1), comprising an essentially circular-shaped housing inner wall (15), whereby a rotating piston (5) is translationally guided in the housing inside a rotor (3) which is connected to a drive or output unit in such a way that said rotor can rotate on a central shaft (4) about the axis (9) of said rotor. Said piston is located in the housing. The piston forms (3) a changeable conveyor chamber (17) defined at least in sections by said piston and rotor. The piston is also provided with an elongate hole-shaped bearing (7). An excentric between the piston and the rotor (3) fixed to the housing and having a circular outer circumference extends into said bearing. According to the invention, the outer circumference of the excentric (6) impinges upon the axis (9) of the rotor. The length (10) of the elongate hole-shaped bearing (7) of the rotating piston (5) is at least two times greater than the diameter of the eccentric(11). The width (12) of the elongate hole-shaped bearing (7) of the rotating pistons (5) is slightly larger than the excentric diameter (11) of the excentric whereby the inner wall of the elongate hole-shaped bearing (7) rolls onto the excentric (6) during the combined rotation-translation-movements. The rotating piston device can be used as a pump or as a motor.

Description

Rotary device

The invention relates to a rotary piston device according to the preamble of claim 1. Devices of this type, in which a rotor and a rotary piston rotate in a housing, the rotary piston or elements connected to it additionally performing a stroke movement, are known in principle and are known as pumps or motor Drives used, but have a large number of sliding parts in their storage and are therefore subject to high wear.

A generic rotary piston device is described in DE-OS 2 010 689, in which the rotary piston executes alternating stroke movements during rotation within the rotor by an eccentric and thereby changes the volume of delivery spaces formed between it and the rotor. Because of the size relationships and arrangement of the eccentric, slot-shaped bearing and eccentricity realized there, the inner wall of the slot-shaped bearing slides frictionally on the outer circumference of the eccentric during the lifting movement, which leads to high wear and susceptibility to maintenance. The invention is therefore concerned with the problem of creating a rotary piston device which can be operated with little wear.

According to the invention, this problem is solved by a rotary piston device with the features of claim 1. The special design, in which the outer circumference of the eccentric just touches the rotor axis and the slot-shaped bearing is slightly wider and at least twice as long as the eccentric diameter, ensures that the inner wall of the slot-shaped bearing during the rotation and stroke movement of the piston on the Exclusively eccentric rolls and no sliding or moving takes place. With these special size ratios, the eccentricity, i.e. the distance of the eccentric center from the rotor axis, exactly half of the eccentric diameter.

The point of contact and pressure between the fixed eccentric and the inner wall of the slot-shaped bearing of the rotary piston describes a circle in a complete revolution of the central shaft in generic rotary piston devices, which forms the guide curve of a hypocycloid. In the device according to the invention with the claimed size and positional relationships, the hypocycloid degenerates into a diameter of the guide circle, ie into a line. When viewed in a coordinate system fixed to the rotor, the respective contact point between the eccentric and the inner wall of the slot-shaped bearing during a rotor revolution describes a circle which corresponds exactly to twice the eccentric diameter in the device according to the invention. The translational movement of the rotary piston relative to the rotor is accompanied by a simple rolling of the inner wall of the elongated hole-shaped bearing of the rotary piston on the eccentric. The The eccentric and the slot-shaped bearing thus form a roller bearing, through which the piston forces are transmitted by simply rolling on the eccentric. Wear on this bearing is minimized because there are no sliding friction components.

In the best case, the rotary piston system according to the invention can therefore consist of only three parts, namely the housing, the rotor and the rotary piston. Since no additional bearing is used, it is also possible to build the rotary piston device according to the invention in extremely small dimensions, which expands its possible areas of application. It is suitable both as a pump, for example vacuum pump, compressor or hydraulic pump, and for use as an engine, such as as a hydraulic motor, internal combustion engine or other expansion machine.

Further advantages and details result from an embodiment of the rotary piston device according to the invention shown in the drawing, which is explained below; show it:

1 shows the individual parts of a rotary piston device according to the invention in an exploded view,

FIG. 2 shows a top view of the assembled rotary piston device from FIG. 1, FIG.

3 shows a section along the line IV-IV in FIG. 2,

Fig. 4 is a section along the line V - V in Fig. 2 and 5 a - f a section along the line VI - VI in FIG. 4 in different rotational positions of the device.

1 shows the basic elements from which the rotary piston device according to the invention is composed. This has a housing body 1 and a cover 2, which together form the housing of the device. A rotor 3 is rotatably arranged in the housing, for which purpose it is firmly connected to a central shaft 4 which, when assembled, protrudes from the housing. The central shaft 4 is used, for example, as a pump with a drive, not shown, or when used as an engine, e.g. Internal combustion engine, connected to an output. A rotary piston 5 is arranged within the rotor 3 in such a way that it also rotates when the rotor 3 rotates, but can additionally perform a lifting movement. This lifting movement of the rotary piston 5 is initiated by an eccentric 6 fixed to the housing, which is attached to the cover 2 eccentrically to the axis of rotation of the rotor 3 and engages in a slot-shaped bearing recess 7 of the rotary piston 5.

The arrangement of the individual components of the rotary piston device and their function can be seen in FIGS. 2 to 5. In the preferred embodiment shown, the eccentric has a circular outer circumference 8, which the rotor axis 9 just touches. The length 10 of the slot-shaped bearing 7 corresponds to twice the eccentric diameter 11 or is slightly larger and the width 12 of the slot-shaped bearing 7 is slightly larger than the eccentric diameter 11. When the rotary piston device is used as a pump system, the force is transmitted from the central shaft 4 from which a rotational movement is initiated in the rotor 3. This takes the rotary piston 5 with it in its rotational movement. At the same time, there is a translational movement of the rotary piston 5 relative to the rotor 3, since the eccentric 6 displaces the rotary piston 5.

For variable use of the rotary piston device, the eccentric 6 can be moved on the housing and can be locked in various positions. Preferably, the eccentric 6 is attached to the cover 2 of the housing, so that by repositioning the cover 2 in a position rotated by 180 ° to the normal position, the delivery flow of the rotary piston device is reversed without the direction of rotation of the central shaft 4 having to be changed.

As can be seen in particular in FIG. 1, the rotor 3 in the illustrated embodiment consists of two opposing cylinder segment-shaped piston guides 13, the outer surfaces 14 of which are rounded with the same or a slightly smaller radius than the housing inner wall 15. The piston guides 13 are rigidly connected to one another and to the central shaft 4 via a plate 16. This embodiment of the rotor 3 is mechanically particularly simple to manufacture, preferably in one piece, and, despite the low weight of the material, is entirely sufficient to carry the rotary piston 5. Ideally, the radii of the outer surfaces 14 of the piston guides 13 and the inner wall 15 of the housing are matched to one another in such a way that the rotor 3 can rotate in the housing in a manner which is free of contact and wear.

FIG. 5 shows the rotary piston device in various rotary positions during half a revolution of the rotor 3, FIG. 5a the position at an angle of rotation of 0 ° and 180 °, FIG. 5b an angle of rotation of 30 °, FIG. 5c an angle of rotation of 60 °, FIG. 5d an angle of rotation of 90 °, FIG. 5e an angle of rotation of 120 ° and FIG. 5f an angle of rotation of 150 °. In order to separate the variable delivery spaces 17 from one another, the rotary piston 5 is of rectangular cross section with two plane-parallel sliding surfaces 18 which slide against corresponding, likewise plane-parallel guide surfaces 19 of the piston guides 13. As a result, surface seals are formed there and between the top and bottom of the rotary piston 5 and the rotor 3 or the cover 2, which are considerably cheaper in terms of their tightness than the line seals which occur in a large number of the devices known hitherto and therefore effectively a backflow of the delivery medium prevent and separate the suction from the pressure side. The seal can be further improved by piston strips (not shown) on the sliding surfaces 18 of the rotary piston 5 and on its sealing surfaces which are in contact with the rotor 3 and the cover 2 at the top and bottom.

Instead of the rectangular cross section of the rotary piston 5, it can also have any other cross-sectional shapes. For example, starting from a rectangular cross-sectional shape, the corners can be rounded, whereby the curves can be so strong that they touch on the narrow sides. This advantageously enables the use of piston rings for sealing. In particular, in an embodiment not shown, the piston can be designed as a round piston with a circular cross section. Here, too, piston rings are used instead of piston strips. The embodiment as a round-bottom flask can advantageously be manufactured particularly precisely. However, compared to a rotary piston 5 with right square cross-section, much larger dimensions can be accepted with the same delivery rate.

As can be seen in particular in FIG. 5, the piston guides 13 in the embodiment shown are dimensioned such that, in the course of a complete revolution of the rotor 3, the feed opening 20 and the discharge opening 21, which can have hose connections or pipe connection flanges, in exactly two positions, namely cover those shown in Fig. 6a at an angle of rotation of 0 ° and 180 °. In the event of rotation, one piston guide 13 opens the discharge opening 21, ie the pressure side, as soon as the supply opening 20 on the suction side is closed by the other piston guide 13. In the case of a largely incompressible delivery medium, this avoids compression in the closed displacement, which would be associated with very high pressures. If the piston guides 13 were larger than the feed and discharge openings 20, 21, a rotation starting from FIG. 6 a in the direction of the position shown in FIG. 6 b would initially keep the discharge opening 21 closed for a moment, while the rotary piston 5 has already moved upwards and the overhead conveying space 17 is reduced and the conveying medium moved therein is compressed. In the case of a design as a compression machine, however, this effect may be desirable and can be achieved in the manner described. If, on the other hand, the piston guides 13 were made smaller than the feed and discharge openings 20, 21, then in the position shown in FIG. In the illustrated embodiment, the feed and discharge openings 20, 21 are formed in the housing inner wall 15. However, it is also possible to move the medium in the direction of To provide rotor axis 9 through, for example, kidney-shaped or sickle-shaped openings in the cover 2 or housing base.

The piston shape selected in the illustrated embodiment with two convexly curved outer surfaces 22 lying opposite one another in the direction of translation movement, the radii of which essentially correspond to that of the inner wall 15 of the housing, is desirable with regard to the most complete emptying of the delivery spaces 17. However, the outer surfaces 22 can also be straight, but then the conveying spaces 17 are not completely emptied.

If necessary, the eccentric 6 of the rotary piston device according to the invention can have a feed line, for example via a central bore and a lubricating nipple for lubricant for lubricating the eccentric wall and the rotary piston 5. Coolant can also be guided past the stressed surfaces of the rotary piston 5 via supply and discharge lines. If there are appropriate openings in the rotary piston 5, lubrication of the sliding surfaces 18 of the rotary piston 5 from the inside of the rotary piston is also possible.

The rotary lobe device according to the invention can preferably also be used as an internal combustion engine, it being possible for 15 troughs or depressions to be provided in the inner wall of the housing for receiving, for example, spark plugs or injection nozzles. As shown, the openings 20, 21 do not have to have additional recesses in the housing inner wall 15 that deviate from the circular shape. The rotary piston 5 can, however, be provided with a recess on at least one of its outer surfaces 22 forms a combustion chamber between the rotary piston 5 and the housing inner wall 15. Such recesses or combustion chambers are preferably provided on both opposite outer surfaces 22 of the rotary piston 5. If the rotary piston device is operated, for example, as a 2-stroke diesel engine, one of the two openings 20, 21 can be omitted. Then there is only one opening in the housing inner wall 15 through which the charge exchange takes place. A motor designed as a rotary piston device according to the invention runs very low in vibration due to the corresponding arrangement of rotary piston 5, bearing 7 and eccentric 6.

In summary, the rotary lobe device described is characterized in that it is low-wear, valve-less, self-priming, safe to run dry and can be installed in any position. It has a high specific delivery rate with a small size combined with the advantages of a piston system. In addition, the simple construction of a few individual parts enables the device to be installed without problems, in particular the piston, and, if necessary, easy replacement of individual elements.

Claims

claims

1. Rotary piston device with a housing with a housing body (1), which has a substantially circular inner wall (15) in circumference, and one in the housing within one with an input or output about a rotor axis (9) on a central shaft (4 ) rotatably connected rotor (3) translationally guided rotary piston (5), which has a slot-shaped bearing (7) into which a housing-fixed eccentric (6) engages with a circular outer circumference, and the variable variable, at least in regions, by itself and the rotor (3) Conveying spaces (17), characterized in that the outer periphery of the eccentric (6) touches the rotor axis (9), and that the length (10) of the slot-shaped bearing (7) of the rotary piston (5) at least twice the eccentric diameter (1 1) corresponds and the width (12) of the slot-shaped mounting (7) of the rotary piston (5) is slightly larger than the eccentric diameter (11), so that the inner wall of the long hole-shaped bearing (7) rolls on the eccentric (6) during the combined rotation-translation movement.

2. Rotary piston device according to claim 1, characterized in that the eccentric (6) is displaceably attached to the housing and can be locked in different positions.

3. Rotary piston device according to claim 1 or 2, characterized in that the eccentric (6) is attached to a cover (2) of the housing, which can be rotated through 180 ° to the normal position on the housing body (1).

4. Rotary piston device according to one of claims 1 to 3, characterized in that the eccentric (6) has at least one supply line for lubricant for lubrication and / or cooling of the eccentric wall and / or the rotary piston (5).

5. Rotary piston device according to one of claims 1 to 4, characterized in that the rotor (3) has two opposing cylinder segment-shaped piston guides (13), the outer surfaces (14) of which are substantially curved according to the inner diameter of the housing and which together and are rigidly connected to the central shaft (4).

6. Rotary piston device according to claim 5, characterized in that the rotary piston (5) is rectangular in cross section with plane-parallel sliding surfaces (18) which are slidably guided on corresponding likewise plane-parallel guide surfaces (19) of the piston guides (13).

7. Rotary piston device according to claim 6, characterized in that the rotary piston (5) on its sliding surfaces (18) has piston strips.

8. Rotary piston device according to claim 7, characterized in that the rotary piston is designed as a round piston with a circular cross section.

9. Rotary piston device according to one of claims 5 to 8, each with at least one supply and one discharge opening (20, 21) in the housing for the conveying medium, characterized in that the piston guides (13) are shaped such that they the supply and discharge openings Cover (20,21) in exactly two positions in the course of a complete revolution of the rotor (3).

10. Rotary piston device according to one of claims 1 to 9, wherein the rotary piston (5) has outer surfaces (22), characterized in that the outer surfaces (22) are arranged opposite one another in the translational movement direction of the rotary piston (5) and are convexly curved, the radii the outer surfaces (22) essentially correspond to that of the housing inner wall (15).

11. Rotary piston device according to one of claims 1 to 10, wherein the rotary piston (5) has outer surfaces (22), characterized in that at least one of the outer surfaces (22) of the rotary piston (5) is shaped such that there is between it and the housing inner wall (15) forms a combustion chamber for using the rotary piston device as an internal combustion engine.