Abstract:
The invention relates to a rotary piston machine which can function as a pump, compressor or motor. A cycloid power component and a correspondingly formed blocking component are in mutual engagement in said machine. The difference in the number of teeth between both components is one. The volume of the working chambers ( 16 ) thus created attains a maximum and a minimum level at each rotation owing to the synchronous rotation of said power component and blocking component.

Description:
[0001]    This application is a continuation in part of Ser. No. 09/485,880 filed on Feb. 17, 2000 the entire disclosure of which is hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention concerns a rotary piston machine as defined by the elements of the independent claim.  
           [0003]    A rotary piston machine for use in a pump, a compressor, a turbine or motor must exhibit properties which allow its design to be precisely calculated. In dependence on the application and the fluid dynamic properties of the medium being transported or pumped, the design of the power and blocking components must be effected in such a way that effective transport performance is obtained. Moreover, the production of these components must be done by means of a tool whose proper design is important in order to minimise production costs.  
           [0004]    In a conventional rotary piston machine (DE P 42 41 320.6; DE G 92 18 694.7; PCT/DE 92/01025), all lines of the cycloid component and the central component extending transverse to and defining the operating direction pass through the point of intersection of the axes of rotation. This limits the expansion and compression behavior of the working chambers and therefore adaptation of the rotary piston machine to various working media and fields of application.  
           [0005]    FR 838,270, GB 1,099,085 and DE 2639760 all disclose rotary piston machines having a power component and a blocking component. The power component and blocking component teeth mutually engage and are configured to have shapes generally of a conical section type (i.e. conical, circular, parabolic, ellipsoidal, or hyperbolic). These teeth shapes of prior art have the disadvantage that a plurality of contact lines occur between the blocking and power components per chamber during operation. This causes reduced efficiency in fluid transport through the chambers and complicates calculation of the pressure and flow properties of the fluid during the course of operation.  
           [0006]    In view of these disadvantages of prior art it is the underlying purpose of the present invention to design a rotary piston machine for a pump, a compressor, a turbine or a motor having a structure which facilitates precise calculation of the flow properties of the medium in the chambers during operation in dependence on the fluid dynamic properties of that medium and which permits efficient design of a tool for producing the power and blocking components.  
         SUMMARY OF THE INVENTION  
         [0007]    This purpose is achieved in accordance with the invention with a rotary piston machine having a power component whose teeth are shaped using a cycloid generator. The cycloid shape not only allows precise calculation of the properties of the rotary piston machine but also produces one line of contact per chamber between the power and blocking components which propagates monotonically through the chamber during the course of operation thereby providing efficient operation of the pump and precise determination of the action of the pump on the transport response of the fluid. The intake and output behavior of the working chambers is determined by the phase shift, to thereby reduce undesired back-flow or mixing between the intake and output working media.  
           [0008]    According to an advantageous embodiment of the invention, the phase shift from the inner to the outer diameter is at least 360° such that the working chamber is closed off from the surroundings at least at one angular position of the first or second component.  
           [0009]    According to a further advantageous embodiment of the invention, the amplitudes of the cycloids forming the operating surface of the cycloid component differ from one another. This allows additional freedom in designing the behavior of the working chambers.  
           [0010]    According to a further advantageous embodiment of the invention, the working chambers are separated by a positive fit between the sides and tops of the opposing component teeth. Due to the different number of teeth, the tooth tops of the control component advance along the sides of the cycloid component teeth to essentially eliminate fluid back-flow. In addition, the control component can thereby be driven by the cycloids.  
           [0011]    According to a further advantageous embodiment of the invention, there is no positive fit between the cycloids forming the operating surfaces of the cycloid component and the control component. The machine is then a flow machine whose characteristics are defined by the impulse and mass of the working medium. Moreover, sensitive media having characteristics impaired by compression may also be used as the working medium.  
           [0012]    According to a further advantageous embodiment of the invention, the control channel for input of the working medium is disposed at the outer diameter, and the control channel for output of the working medium is disposed on the inner diameter of the tooth structures. During turbine or motor operation, the impulse and mass forces generated by the working medium are aligned with the direction of displacement of the working chamber. This reduces leakage losses and improves efficiency.  
           [0013]    According to a further advantageous embodiment of the invention, the working positions of the axes of rotation of the components can be changed independently of one another. In accordance with the invention, additional pairs of toothed disk structures can be incorporated. At least one of the components has toothed gearing on its back side which cooperate with an additional rotating component having single or double teeth. This requires a radial seal between the enclosing casing and these rotating components. Drive and output may be effected in a conventional manner using shafts or toothed wheels connected to the rotating components or disposed thereon and cooperating with additional drive or output means. By changing the working positions of the rotary axes, the volume change in one component of the rotary piston machine can be advanced or retarded with respect to the other to permit graduated operation through connection of the working chambers or for mixing.  
           [0014]    According to an advantageous embodiment of the invention, there are two cycloid or control components and the additional part is disposed between the doubled components in the form of a ring with toothed surfaces or cycloid operating surfaces. According to a further embodiment, at least two working chambers, on opposite sides of the ring, can be connected to one another. This creates e.g. a double pump or power machine, in which a control component, with teeth on both sides, is disposed between two absolutely synchronously rotating cycloid components with a number of teeth differing by one tooth from the number of teeth on the doubled components. This control component may comprise a drive or output device in dependence on whether it is a pump or a motor. Alternatively, the drive and/or output may be effected via the doubled cycloid components. The casing may serve as a stator supporting both driven cycloid components at corresponding working angles between which the control component, having sides with a number of teeth differing by one tooth, freely rotates.  
           [0015]    According to a further advantageous embodiment of the invention, the casing or the control component has appropriate channels for the input or output of the working media, which may be optionally controlled during rotation. This precludes additional valves and also effects rinsing in the centrifugal direction.  
           [0016]    According to a further preferred embodiment of the invention, the radial circumference of the components is spherical, and the components are guided on a corresponding spherical inner surface of the casing in a radially sealing manner. This spherical guidance permits change in the working position without creating additional sealing problems. This outer or inner radially sealing, spherical working chamber wall may be connected to the control or cycloid components and may rotate therewith to center the components with respect to each other.  
           [0017]    In a further advantageous embodiment of the invention, the rotary piston machine is a compressor with control independent of the rotational speed effected, in particular, by changing the phase shift of the two rotating parts relative to the channels of the working media. In addition to the advantageously stable centrifugal force dependence of the moving components, the small size, and large power, the phase shift permits continuous control of the compression ratio, independent of the rotational speed. Such a compressor is particularly suitable for charging combustion engines, since they have high, widely varying rotational speeds, since the mass of the charger should be as small as possible (in particular the driven rotating masses), and since the power must be controlled independently of the rotational speed. Since several pairs of working chambers can operate in a phase-shifted manner, the valve-less control in the direction of flow (no inversion of flow) and the very high sealing quality of the working chambers, permit the inventive compressors to be used in pressure ranges currently accessible to piston machines only.  
           [0018]    In a further advantageous embodiment of the invention, the rotary piston machine is a hydrostatic element used as a pump, motor or transmission. These applications are advantageously influenced by the extremely favorable relationship between the size and volume exchange. The simple kinematics, the rotational speed stability of the structure and the very large rinsing channel cross-sections ensure that these machines are also suitable for the highest of rotational speeds. The inner flow resistance of the machine according to the invention is extremely low. If it is used as a pump, the high inherent stability of the components has advantageous effects. Wear is limited to rubbing between the movable components. In addition, the machine is suitable for the highest working pressures. If it is used as a hydraulic motor the same advantages obtain, in particular, the small accelerated masses, the good starting behavior, and the high volume efficiency. The low construction volume and the compact manner in which the pump and the hydraulic motor can be connected is particularly advantageous for use as a hydrostatic transmission.  
           [0019]    In a further advantageous embodiment of the invention, the rotary piston machine is a power machine or refrigerator, in particular, operating according to the Stirling principle, wherein the cooperating working chambers are phase-shifted by 90°. Two rotating cycloid components cooperate with a rotating control component to form operating chamber pairs which are each phase-shifted by 90°. One chamber is heated and the other cooled, and a regenerator is integrated into the control component. In accordance with the invention, there is no component exchange between the warm and cool regions. The walls of the cold and the warm working chambers are insulated from one another despite their close spatial proximity. An advantageous convection surface/working chamber volume ratio can be achieved due to the high inherent stability of the components forming the working chamber. One of the rotating components may be a linear generator driver for a Stirling motor or a linear motor for a Stirling refrigerator. The machine can therefore be hermetically sealed and designed for very high loading pressure with low working gas leakage loss. The phase shift defining the performance of the Stirling motor can be easily realized in this embodiment. In any event, the amount of transported heat can be regulated in such a refrigerator, irrespective of the rotational speed.  
           [0020]    Further advantages and advantageous embodiments of the invention can be extracted from the following description, the drawing and the claims.  
           [0021]    Embodiments of the invention are shown in the drawing and further described below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0022]    [0022]FIG. 1 shows an exploded view of a drive or output component and a blocking component;  
         [0023]    [0023]FIG. 2 shows a drive or output component and a blocking component in the assembled state, including the casing;  
         [0024]    [0024]FIG. 3 shows a top view of a cycloid tooth construction with 4 cycloids and a spiral angle of approximately 170°;  
         [0025]    [0025]FIG. 4 shows a top view of a corresponding tooth construction of the blocking component with five teeth;  
         [0026]    [0026]FIG. 5 shows a schematic illustration of the geometric means with which the structure of the cycloid teeth of the power component are generated;  
         [0027]    [0027]FIG. 6 shows a side view, partially cut, of the rotary piston machine of FIG. 2, indicating inlet and outlet openings;  
         [0028]    [0028]FIG. 7 shows a further embodiment of the rotary piston machine in accordance with the invention having upper and lower power components and an intermediate blocking component;  
         [0029]    [0029]FIG. 8 shows another embodiment of the double power component single blocking component embodiment of FIG. 7, with co-linear orientation of the drive axes;  
         [0030]    [0030]FIG. 9 shows a further embodiment of the invention indicating a gap between the power component and the blocking component; and  
         [0031]    [0031]FIG. 10 shows a plan view onto the toothed portion of the power component, illustrating the spiral nature of the cycloid teeth with a spiral in excess of 360 degrees. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    The right hand side of FIG. 1 shows the power component  1  and the drive or output shaft  2 . One end of the drive or output shaft  2  supported in the casing (not shown) is provided with the power component  1 . The power component  1  consists of a spherical layer  3  which is bordered by a flat base surface  4  at the drive or output shaft  2  with an end face  5  having a spiral, cycloid toothed structure. In contrast to the conventional cycloid construction, the cycloid  6  is generated by rolling a circle along the line of intersection  7  between spherical surface  8  and base surface  4  with the point on this circle describing the cycloid  6  always being located on this spherical surface  8 . The cycloid  6  is the generating curve for forming the toothed structure. A straight cycloid toothed structure is obtained by a straight generating line moving about a fixed point on the rotary axis of the drive or output shaft  2  along the generating curve  6 . Instead of such a straight generating line, a spiral generating line leads to the spiral cycloid tooth structure of the power component according to the invention.  
         [0033]    The blocking component  10  shown on the left-hand side of FIG. 1 has a similar geometrical shape. A shaft  11  disposed in the casing (not shown) supports the spherically layered blocking component  10  which is bordered by a base surface  12  proximate the shaft  11  and having a spherical outer surface  13 . The end face  14  of the blocking component  10  comprises a spiral tooth structure, wherein the number of teeth exceeds the number of teeth in the cycloid  6  of the power component  1  by one. The shapes of the teeth correspond to the tangents to the cycloids  6  during the synchronous rotation of the power component  1  and the blocking component  10 . The shape of the teeth may be selected to maintain a defined separation between the cycloid and the teeth of the blocking component  10 . In this case, the displacement machine then becomes a flow machine. This is advantageous if e.g. the working medium could be damaged by compression at the sealing lines  9  or if the impulse and mass forces of the working medium are to be used. The rotary axes of the blocking component  10  and power component  1  are disposed at a working angle  15  with respect to one another. It is irrelevant to the invention whether the cycloid tooth structure is disposed on the end face of the power component  1  as shown herein, with the corresponding tooth structure disposed on the blocking component  10 , or vice versa.  
         [0034]    [0034]FIG. 2 shows the power component  1  and the blocking component  10  in their installed position. Two sealing lines  9  between the power component  1  and blocking component  10  are shown (visible as contact points in the drawing). The blocking component  10 , the power component  1  and the casing  17  form several working chambers  16  in dependence on the number of cycloids, of which two are shown. In the rotational direction of the power component  1  and blocking component  10  indicated by two arrows, the working chambers  16  expand during the part of the rotary motion shown. The volume of the working chamber is correspondingly compressed in the second half of the rotation (not shown). The sealing lines  9  move from the outside to the inside or vice versa, depending on the direction of rotation, to thereby effect supply of the working medium or drive of the output shaft  2 . The control openings in the casing  17  (not shown) are located in dependence on the requirements of the application. During pump operation with supply from the inside to the outside, the inlet opening in the casing  17  is located at the point where the sealing line  9  exits the inner diameter of the toothed structure. The outer toothed structure is disposed at a position in the casing leading to the required volume of the working chamber  16 . The power output of the rotary piston machine may be regulated for constant rotational speed by moving the blocking component  10  relative to the power component  1 . In this case, the rotary axis of the blocking component  10  remains on a cone-shaped surface having a cone angle corresponding to the working angle  15 .  
         [0035]    [0035]FIG. 3 shows a simplified top view of the power component  1 . Four spiral generating lines  18  are shown, illustrating the structure of the spiral cycloid teeth. The generating lines  18  are located at the apex points of the cycloids. In the example shown, the spiral angle  19  is approximately 170°.  
         [0036]    [0036]FIG. 4 shows the corresponding generating lines  21  for the blocking component  10 . A comparison between FIG. 3 and FIG. 4 shows the difference in the number of teeth and illustrates the effect of the spiral tooth structure. In contrast to a straight cycloid tooth structure, the same working chamber may expand and compress simultaneously at its inner and outer regions. This facilitates a plurality of designs to obtain a desired volumetric behavior for the working chamber. When the spiral angle  19  subtended by the spiral generating line is greater than 360°, each working chamber  16  is temporarily closed at all sides during rotation of the power component  1  and the blocking component  10 . Back-flow of the working medium or other effects between the outlet and the inlet side or vice versa are thereby precluded.  
         [0037]    [0037]FIG. 5 illustrates the manner in which the spiralling cycloid tooth structure of the power component is generated. The cycloid teeth are generated by rolling a circle  30 A,  30 B,  30 C, along a respective base circular path  32 A,  32 B,  32 C. As the respective circle  30 A,  30 B,  30 C rolls along the respective base circular path  32 A,  32 B and  32 C, an associated cycloid structure  32 A,  32 B,  32 C is generated. By finely stepping the radius of the base circle  32 A,  32 B,  32 C starting, for example, with the internal circle  32 A, successive neighbouring cycloid shapes can be generated which can be smoothly connected to one another. The spiralling nature of the progressive cycloid structure when moving from the inner radial portion of the power component to the outer portion is determined by a generating spiral  36 . With successively stepped radii for the base circles  32 A,  32 B and  32 C, the generating spiral  36  determines the initial position of the respective rolling generating circle  30 A,  30 B,  30 C which is offset relative to that of the neighbouring rolling generating circle  32 A,  32 B,  32 C such that the neighbouring cycloids are shifted with respect to each other. Smooth connection of the neighbouring crests of cycloids generated on adjacent base circles  32 A,  32 B and  32 C leads to a spiralling or curved cycloid tooth structure when moving from the inside of the power component towards the outside portion thereof. In the example of FIG. 5, only  3  such sweeps are shown for reasons of clarity. In actuality, small steps of increasing or decreasing radii are performed in order to smoothly generate non-linear, radially extending cycloid teeth on the power component.  
         [0038]    [0038]FIG. 6 shows a partially cut side view of a power and blocking component of the embodiment in accordance with FIG.  2 . The reference symbols here correspond to those of FIG. 2 and are therefore not further discussed. FIG. 6 shows the additional features of an inlet  40  and an outlet  42 . In the embodiment of FIG. 6, the inlet extends axially through the central portion of the blocking component  10  to access the chambers  16  between the blocking component  10  and the power component  1  at a radially inward portion of the rotary piston machine. As the power  1  and blocking  10  components rotate, a medium passing through inlet  40  is transported from the inside to the radially outer portion of the rotary piston machine where it can be extracted at outlet  42 . Outlet  42  can be confined to a certain peripheral region of the casing  17  of the rotary piston machine or extend through an annular region thereof.  
         [0039]    [0039]FIG. 7 shows an embodiment of the rotary piston machine in accordance with the invention having a first power component  50  and a second power component  52 . These power components  50  and  52  engage blocking component  54  located between the respective cycloid surfaces of the first and second power components  50 ,  52 . In the embodiment of FIG. 7, the power components  52  and  50  are disposed at an angle with respect to each other and the centrally disposed blocking component  54  is designed with teeth structures which are symmetric with respect to a plane extending through the central portion of the blocking component  54 .  
         [0040]    In the alternative embodiment of FIG. 8, the first power component  60  and a second power component  62  are configured to extend along a common vertical axis. In such embodiments, the blocking component  64  must be structured in such a fashion that an effective tilt symmetry axis is present with regard to the upper  65  and lower  66  teeth structure of the blocking component  64 . In the embodiment of FIG. 8, the number of teeth  65  on the upper surface on the central blocking component  64  and the number of teeth  66  on the lower portion of the blocking component  64 , are equal. Other embodiments are possible in which the number of upper teeth  65  and lower teeth  66  are different with respective differences in the cycloid formations on the first  60  and second  62  power components. Alternatively or in addition thereto, the tooth-like structures  65  and  66  can be displaced in angle with respect to each other. Both these features can be used to phase shift and change the time dependence of the transport behaviour of the rotary piston machines, in particular when adjacent or neighbouring chambers such as  67  and  68  are arranged such that the medium transported thereby are joined together in parallel.  
         [0041]    In the embodiment of FIG. 9 the power component  70  is displaced with respect to the blocking component  72  to exhibit a gap  74 . Such gaps can be extremely thin and be filled by the fluid medium being transported in the rotary piston machine. The size of the gap  74  can depend on the properties of fluid being transported (viscosity etc.).  
         [0042]    [0042]FIG. 10 shows a plan view of the cycloid tooth structured side of the power component. The spiral structure extends from an inner diameter  84  to an outer diameter  86  and displays spiralling crests  80  and  82  travelling through an angle of approximately 360 degrees while progressing from the inner radius  84  to the outer radius  86  of the power component. The structures  80  and  82  correspond to the spiral generating curve  36  of FIG. 5.  
         [0043]    All the features shown in the description, the subsequent claims and the drawing may be essential to the invention individually or collectively in any arbitrary combination.  
                                        1   power component        2   drive or output shaft        3   spherical layer        4   base surface of the power component        5   end face of the power component        6   cycloid        7   line of intersection between spherical surface and base           surface        8   spherical surface        9   sealing line between power component and blocking component       10   blocking component       11   shaft       12   base surface of the blocking component       13   spherical surface       14   end face of the blocking component       15   working angle       16   working chamber       17   casing       18   generating lines of the power component       19   spiral angle       20       21   generating lines of the blocking component       30A   first rolling generating circle       30B   second rolling generating circle       30C   third rolling generating circle       32A   first base circle       32B   second base circle       32C   third base circle       34A   first cycloid       34B   second cycloid       34C   third cycloid       36   generating spiral       40   inlet       42   outlet       50   first power component       52   second power component       54   blocking component       60   first power component       62   second power component       64   blocking component       65   upper teeth       66   lower teeth       67   upper chamber       68   lower chamber       70   power component       72   blocking component       74   gap       80   first generating spiral       82   second generating spiral       84   inner diameter       86   outer diameter