DE2262776A1 - RADIAL PISTON MACHINE - Google Patents

Description

DR. ING. E. HOFFMANN · I) IPiL. ING. W. EITLE · BR »RER. NAT. E. HOFFMANN

PATENT LAWYERS D.8000 MÖNCHEN 81ARABELLASTRASSE 4 TELEPHONE (0811) 911087

5 169/7O

Rederi AB Soya, Hagersten / Sweden

Radi piston machine

The invention relates to a radial piston machine which can be used as a pump, compressor or motor is intended with a centrally arranged fixed slide axis on which a rotor with radial cylinders is mounted, within which pistons can be moved inward and outward with respect to the slide axis, and with a circumferential ring rotatably arranged around the rotor about an axis eccentric to the slide axis and Rollers between the outer end faces of the pistons

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imd a track for the rollers on the inside of the Circumferential ring are arranged and are used for movement between the rotating ring and the rotor during the rolling caused by the eccentricity both to as also to be transferred from a raceway for the rollers, which is formed on the piston end faces.

Rotary machines of the above-mentioned type with radial pistons are known in the art. An example of this describes Swedish patent specification 325 479. A A special feature of such rotary machines is that neither an external torque from the rotor the machine is added to the runner. Instead, the torque is transmitted via the rotating ring.

In the radial piston machine mentioned above, the rollers roll on the end faces of the pistons over a distance back and forth which corresponds to the eccentricity. Each angular position of an individual piston in the machine corresponds a certain position of the role, which is determined by the geometry of the machine and the achieved Circumferential loading conditions. The rollers are pressed against the rotating ring on the by means of contact pressure one side and the piston end faces held in their seats on the other side. The main parameters which master the geometry of the movement of this machine are the eccentricity, the diameter of the rotating ring and the diameter of the rollers. The loading conditions will be by the ratio between the piston forces in the part of the machine where the pressure medium (working medium) is below high pressure and determines the corresponding piston forces in the part where the pressure is low. With piston forces here are the hydraulic forces and the forces of the

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Piston suspension in the cylinder chamber plus the inertial forces in the form of centrifugal forces. All these Forces are directed in such a way that they help increase the contact forces on the rollers. The designation In the following, "hydraulic forces" are to be viewed in such a way that they are not only fluid pressure, but also gas pressure includes in possible applications in which the working medium is a gas. However, acts on the piston yet another force, which is determined by the hydraulic pressure and in the rotor and the slide axis surrounding housing of the machine is obtained. This hydraulic pressure, hereinafter referred to as "drainage pressure" is referred to,. occurs through the flow of the pressure medium into the housing of the machine through the sealing gap between Pistons and cylinders and runners and slide axis on. the The pressure head is there due to the inflow and the obstructions determined on the outflow path from the housing of the machine. Another occurring under certain conditions The effect, as has been established, is the changes in the displacement of the rotor and the pistons due to torsional vibrations. The force acting on the pistons due to the evacuation pressure counteracts the previously mentioned forces and so tends to affect the contact forces to decrease on the roles. The limits for the contact forces depend on the evacuation pressure and are generally on the pistons / rollers that work in the low pressure area of the machine and especially on the outer end surfaces of these pistons, where the forces of the piston suspension are lowest, are generally very small. If these limits are reduced to such an extent that the contact forces are brought to zero, the roles can be made to move under the

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To move the effect of accelerations out of their geometrically determined positions.

In a radial piston machine known in the art from German patent specification 953 223, the difficulty is of arranging the rollers with respect to the corresponding pistons is partially solved by the fact that the outer End faces of the pistons are provided with lips which limit the movement of the rollers in the circumferential direction. However, in this case, the lips not only limit the movement of the rollers, but also mainly a drive function between the rotor and the surrounding housing in combination with the rollers is achieved. However, this arrangement does not ensure that the roles their position with respect to the corresponding Maintain the piston if the pressure in the housing exceeds certain values.

The invention is based on the object of an operation with higher evacuation pressure than before, i.e. with lower limits for the contact force while at the same time accurate positioning of the rollers with respect to the end face of the piston is fully ensured. Simultaneously the application of such high evacuation pressure should be made possible that the reciprocating movement of the piston with the result that the pumping action of the machine ceases, or in other words, disengagement come occurs.

This object is achieved according to the invention in that holding elements to hold the rollers in their position in front of the piston end faces in contact with or near the raceway are provided on the circumferential ring, even if the pistons

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are retracted into their cylinders so far that the contact between the rollers and the end faces of the piston has been lost.

The main features of the designed according to the invention Radial piston machines are as follows:

1.) Full reliability what the arrangement of the Roles in relation to the associated piston end face concerned, in the event that the contact forces go completely to zero and the piston moves away from the roller.

2.) The retaining elements do not require any moving parts that would otherwise occur during normal continuous loading? drift would be worn out; there is only fluid friction.

j5.) The dimensions of a machine (both in radial as well as the axial direction) with a given displacement do not have to be due to the inventive Design features are increased and are actually similar to those of a machine without the inventive Design features comparable.

In a preferred exemplary embodiment of the radial piston machine according to the invention, the holding elements have fixed ones Stop devices on the sides of the rotor surfaces, which have edges on one side of each piston, the serve to limit the movement of the rollers on the piston end faces. The roles, in turn, are preferred with axial, .leitenden pins which are fitted into grooves arranged on the circumference. The grooves are in

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attached to the end plates connected to the circumferential ring. The den are more preferably to the Ends equipped with flanges which interact with the surrounding guide surfaces on the circumferential ring.

In a particularly advantageous embodiment of the radial piston machine according to the invention, the end positions are of the roller at the piston end surface by interaction between the flaps of the roller and the edges of the attacks determined. The stop point in each outer layer is arranged so that the contact force between roller and piston in this position gives a moment around the central axis of the slide axis, the moment tending to move the rollers further inward from the outer layer on the end face of the piston to move.

In summary, it can be said that the characteristic feature of the exemplary embodiments as described in the claims are defined, is that the position of the rollers relative to the outer end face of the pistons (which will be referred to below is referred to as a raceway) partly through interaction between the axial, leading pins of the Rollers and the circumferential grooves in the end disks of the rotor is determined, the rollers on Moving from the contact surface of the circumferential ring under the effect of radial accelerations are prevented and partly by the stop devices, which are adapted to the runner surfaces and serve to the rollers on leaving the zone in the path of the piston roller raceway and the cylinder opening under the effect of tangential accelerations to prevent. As already mentioned, occurs

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the need for a special arrangement of the rollers only in cases where the contact forces on the rollers can be reduced to zero. .

Further advantages and features of the radial piston machine according to the invention are detailed in the following Description explained in more detail with reference to the embodiment shown in the drawing. It demonstrate:

Fig. 1 is a radial section of the invention Machine through one of its cylinders,

Figure 2 is an end view of the machine

Slide shaft with one end of the housing removed, and

3 shows a diagram of the design principles which are used to reduce the effect of the holding elements be applied to the overall dimensions of the machine.

Fig. 1 shows the structure of the machine. The slide axis 1 also carries the hydrostatically mounted rotor 2 like the housing of the machine, consisting of the rotating ring 3 and the end plates 4 and 5 · The housing of the machine is in relation to the rotor by means of roller bearings and 7 eccentrically mounted on both ends of the slide axis. The end face 8 of the slide axis is called mechanical and hydraulic coupling level designed for the machine. Two axial main lines lead from this level to the two slide openings 10 and 9 for the high pressure or Low pressure side of the machine. The slide openings

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9 and 10 are cyclical with the individual Zyllnderkammexn in connection. Another line 32 also extends from the end face 8 and connects directly to the interior of the housing the machine is in communication. Leakage fluid is drained through this line.

In the cylinder chamber 11, the piston 12 moves as a result of the change in the distance of the bearing point on Circumferential ring from the central axis 30 of the rotor during the rotation back and forth, which in turn depends on the eccentric distance between this central axis 30 and the central axis 27 of the annular ring depends. The level 13 * in which the two central axes 30 and 27 lie, is called the plane of eccentricity. This level has a dual functional importance. First, it is it is the plane in which the two turning points of the pistons in the cylinder chambers are reached, and secondly it is the level, which the piston-cylinder equipment of the machine with a working medium with low pressure working side and a working with a working medium with high pressure side divides.

The piston 12 is loaded in the cylinder chamber by two concentric compression springs, which in the illustrated Embodiment consist of two coil springs 14 and 15 with opposing turns. The reason for the provision of two springs is firstly that they achieve the maximum possible spring force can be obtained in the available space, and secondly, the risk that the piston will rotate in the cylinder chamber tends to be minimized when contact with the roller is lost. As from the above becomes clear, the main task of these feathers is to

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a mechanical pressure force on the piston 12 in addition to bring about the hydraulic and inertial forces acting on it. Because the hydraulic forces are values can assume that can range from full vacuum (in the pressure medium) to full working pressure, what mainly on the compressibility of the pressure medium and the pressure changes caused by it in the hydraulic system depends, it's easy to see why the previously mentioned superimposed spring forces are required to produce positive contact forces in most working conditions between the piston 12, the roller 16 and the rotating ring 3 maintain.

The cylindrical roller 16 is concentric at its ends Splash 17 and 18 provided, which are slightly conical in the direction of the roller surface, and with corresponding bevels on the inner edges of the circumferential ring cooperate. A job for this splash consists in guiding the movement of the roller so that its generatrices remain parallel to those of the orbit.

however, in the case of the present invention, it became this Flanges have another task, namely that they have stops for the tangential arrangement of the rollers form relative to the piston roller path or to the path * According to the invention the radial limitation of the movement of the rollers is ensured by placing in the zone axially behind the flanges the rollers with cylindrical pins 19 and 20 were provided with the opposite concentric grooves 21 and 22 on the inside of the end plate 5 and 4 are engaged.

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With regard to the tangential arrangement of the rollers 1st it is uncomfortable due to the puncture as well as the space, to use the previously mentioned known solutions, the end faces of the pistons with stops for limiting the rolling motion of the rollers are provided. This is the case with the radial piston machine according to the invention with your special work process so «due to the The fact that the machine is suitable for such a large eccentricity in relation to the piston diameter that the tangential points of the rollers at certain angular positions outside the limit of the generatrix of the piston * lie (see angular position «- 270 ° in Fig. 2). Because during about half a turn (if the angle « between 90 and 270 °) the piston end faces in the cylinder within the outer diameter of the rotor retracting would be a hypothetical locking arrangement this way the radial dimensions of the machine increase drastically.

Also is the limiting puncture which is divergent Opening surfaces 28, 29 in the runner in combination only with the pins 19, 20 and the grooves 21, 22 not satisfactory. These divergent surfaces actually only have a tangential limiting effect if the angle <* is between 80 and 270 °.

Another theoretically conceivable solution is “fitting in” of radially movable pins on each side of the piston and parallel to its center line, which face outwards are spring loaded, in combination with the ones mentioned above Tenons and grooves. But such a solution would be inconvenient in the vast majority of cases. In the first place you would such pegs over with one revolution of the machine

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have to move a distance which corresponds to twice the eccentricity, i.e. at the outer turning point (<* = 0 °) and an equally large part of the journal would have to protrude from an associated guide hole in the runner. In addition, a certain proportion of the pin would have to remain within the guide hole, whereby the lateral reaction forces would be so great that plague eating occurs. At the inner turning point (<x = 180 °) the guide hole should be deep enough to accommodate the full length of the pin and any coil spring that may be present. However, in Most of the time taking into account the space available such an arrangement in the limited, between make the available sectors appear impractical for the piston and the center plane of the rotor. Second would such a solution, assuming it was from the point of view of the available space, an unsatisfactory service life due to unavoidable wear and tear result.

In the present invention, this critical problem is solved differently by providing fixed retaining plates 25 and 26 for the rollers on the rotor at equal distances from the plane of symmetry of the rotor through the cylinder axes and with a distance between them which is equal to that between the median planes of the flanges 17 and 18 of the rollers 1st. The radial extent of the plates 25 and 26 is limited by a circle concentric with the runner, the radius of which is so large that these plates move downwards in the inner reversal position (<* = 180 °), in the grooves 2J> and 24 there is a minimal radial play between the end surfaces and edge surfaces of the circumferential ring. At the outer reversal point (<x = 0 °) the play is increased by twice the eccentricity (Fig. 3).

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Around each cylinder mouth, the plates form a symmetrical opening, inside which the puddles of the rollers can freely follow the normal movements of the rollers without being touched by the edges j51 of the Plates come into contact. The following are normal movements:

The movement cycle performed by the rollers over the piston roller path (raceway) during a Rotation of the machine when the latter is unloaded, i.e. one set of the rollers is completely symmetrical with respect to the plane IJ the eccentricity is arranged when a pair of cylinders through this Level goes through.

The rolling distance, which is caused by the rotation of the rotor relative to the housing of the machine at maximum Torque load is determined.

A certain fixed roll distance that defines the permissible torsional vibrations of a certain amplitude around the position of equilibrium under load is equivalent to.

By adding up the three amounts of movement mentioned above and considering that the machine is reversible is the width of the openings in the retaining plates for the rollers.

For reasons already mentioned, the minimum limits are the Retaining plates for the rollers at the outer reversal point (oc = 0 °) the piston with a view to being driven by the splash of the rollers. Taking into account that the width of the

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opening of the holding plate for the rollers according to the above Designs is fixed, the only way to reduce the limits to a minimum is that the diameter of the flanges of the rollers and the outer diameter of the retaining plates for the rollers are limited will. The own diameter of the roll is fixed. The practical criterion for determining the other two diameters is clear from Fig. J5. It is hypothetically assumed here that the piston is in front of the outer reversal position has lost its contact with the roller at the same time as the moment equilibrium on the runner has lost the one or other reason is disturbed, so that the rotor is immediately rotated forward to the position where the corner of the retaining plate 25 reached level I5 of eccentricity for the role Has. It is also assumed that the flanges of the rollers at this point are at the same time at the corners of the Lay the retaining plate on hard, as shown in FIG. 3. Because the cylinder chamber is now in contact with the pressurized medium under high pressure, the contact force R (between piston and roller) is also due to the pressure determined and can therefore assume high values. The product the contact force R and the distance of the lever arm from the center axis of the rotor determine the torque contribution of the piston to the moment equilibrium of the rotor. As can be seen from FIG. 3, this is moment contribution so that it tries to turn the rotor back relative to the housing of the machine and spontaneously turn the role into its exact position Position back to the piston roller path. The theoretical limit for both of the aforementioned diameters is determined by the condition which is obtained when the roller is partially on the corners of the stop surfaces (Edge Jl of the plate) and rests partially on the edge of the piston in such a way that in some points of contact just a slide starts when the reel is back

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Roll on the piston roller path, i.e. on the raceway got to. Such lengths come about for a variety of reasons, including unacceptably high surface pressures not embossed for practical design. As a result the dimensioning of the retaining plates for the rollers and the flange diameter of the rollers is chosen so that the direction of the contact force R in the aforementioned hypothetical case is essentially parallel to the longitudinal axis of symmetry of the corresponding cylinder runs. The limits that are safely adhered to are completely appropriate for the drive of the rollers, as by Attempts was confirmed. This is true regardless of whether the working conditions relieve time the piston or its deliberate pressing into account. .

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Claims (5)

Claims Radial piston machine intended for use as a pump, compressor or motor with a centrally arranged fixed slide axis on which a rotor with radial cylinders is mounted, inside whose pistons are displaceable inwards and outwards with respect to the slide axis, and with one around the Runner rotatable about an axis eccentric to the slide axis arranged rotating ring and rollers, which between the outer end surfaces of the pistons and a raceway for the rollers are arranged on the inside of the rotating ring are and serve to move between the rotating ring and the runner during eccentricity-induced rolling both to and from a raceway for the roles, which is formed on the piston end faces, to be transferred, characterized that holding elements (25) for holding the rollers (16) in their position in front of the piston end faces in contact with or in the vicinity of the raceway on the circumferential ring (j5) "provided are, even if the pistons (12) are retracted so far into their cylinders (11) that the contact between the rollers (16) and the end faces of the piston has been lost. 2. Radial piston machine according to claim 1, characterized. That the holding elements (25) on the lateral end faces of the runner (2) fixed stops with supporting edges (31) on each side of each Piston (12) », which causes the movement of the rollers (16) can be limited on the piston end face. - 16 - 309827 / 0-422 3. Radial piston machine according to claim 1 or 2, characterized in that the rollers (16) are provided with axially guiding pins (19 * 20), which are attached to the circumference in the circumferential ring (3) End disks (4, 5) arranged grooves (21, 22) are fitted. 4. Radial piston machine according to one of the preceding claims, characterized by leaning that the rollers (16) at the ends flap (17, 18) on * have which cooperate with the surrounding, leading surfaces of the circumferential ring (3). 5. Radial piston machine according to claim 2, characterized in that the end positions of the rollers (16) on the piston end face by working together »wipe the splashing (17, 18) of the rollers (16) and the edges (51) the holding elements (25) are limited, the stop point is arranged in each outer layer so that in this position the contact force (R) between roller (16) and piston (12) a moment around the center line of the slide axis (1) Increase notifies, whereby the moment tends to continue the roller (16) from the outer layer on the end face of the piston bring inward. 309827/0422