DE2416772A1 - Pump with radial piston rotor on ported shaft - has piston motion controlled by eccentrically rotating ring coupled to drive shaft - Google Patents

Abstract

The pump is of the type having a rotor carried on a ported shaft and containing a number of radially reciprocating pistons whose motion is controlled by a rotary ring carried in the housing and having an internal polygonal cross-section engaged by the pistons via supporting shoes. The ring being eccentric relative to the axis of rotation of the rotor and being connected to the drive shaft. The drive shaft is carried in bearings in the housing, independently from the ring. The drive shaft is connected to the ring via a coupling which absorbs any mis-alignment between them without transmitting undesirable forces.

Description

Radialkolbenmas chine The invention relates to a radial piston machine according to the preamble of claim 1. These are so-called path-controlled Radial piston pumps and motors for the hydrostatic conversion of mechanical energy in pressure energy or vice versa, whereby oil is usually used as the working medium will. The displacement volume per revolution can be constant or adjustable, the adjustment by moving the control pin and thus by offsetting the axis of rotation of the cylinder block to the axis of rotation of the piston guide ring takes place.

In a known radial piston machine of this type (DT-OS 2 134 944) the piston guide ring is rigid with the drive shaft via a lateral support disc tied together. Thus, the piston guide ring and the drive shaft are together in the machine housing stored, on the one hand on the drive shaft itself and on the other hand via a further support washer, rigidly connected to the piston guide ring, which has a hollow one Has bearing journals. Each of the bearings, which are designed as plain bearings, have two of them diametrically opposed relief pockets, which are connected to the pressure via channels or are connected to the suction line in order to create a hydrostatic Compensation of the radial "hydraulic system forces" acting on the bearings (das are the forces caused by the working fluid in the cylinders) and thereby to reach an @@@@@@@@@@@@@ @@@ @@@@@@@ and abniitzung in the camps. For axial guidance of the rotor consisting of piston guide ring and drive shaft in the machine housing Corresponding pairs of sliding surfaces are provided.

This known construction has the big disadvantage that - by the common storage for the piston guide ring and the drive shaft - any of Radial or axial forces acting at least partially on the outside of the drive pin be transferred to the housing via said plain bearings, so that in spite of the Compensation of the radial hydraulic system forces in the unbalanced plain bearings Forces are effective, friction and wear and tear or even damage from seizure cause. In particular when using the radial piston machine as a motor it often happens that the torque decrease from the drive pin via gears or takes place via a belt drive, the action of external forces on the driving pin is inevitable. In the case of the known machine, this can be initiated of external forces also have the consequence that the axes of the Z-X cylinder block and the piston guide ring are no longer exactly parallel to each other, which in turn Wear, especially on the piston shoes and on the piston guide surfaces, or an increase in leakage losses.

The invention is therefore based on the object according to the preamble of claim 1 trained radial piston machine to the effect that friction even in the presence of external forces acting on the drive shaft and wear in the bearings and on the piston guide surfaces as much as possible is avoided.

This task is accomplished through the application of the distinguishing features of claim 1 solved. Thereafter, those arranged on the piston guide ring are now used Bearing exclusively to support the piston guide ring. Although this has to The result is that the drive shaft is mounted independently of the piston guide ring an e @@ @ higher effort is required for stock; but one reaches here majorly @@@ @ Decisive advantage that something that might occur from outside on the driftwiL '? acting forces entirely from the bearings of the piston guide ring and from d »-l to axial guidance of the piston guide ring serving sliding surfaces are kept away, and that neither such forces; more of a taper of the piston guide ring effect opposite the cylinder block can. So it's done the invention the decisive causes for the occurrence of friction and wear as well as any storage damage eliminated from the ground up. The feature b) is essential to achieving this success. Namely, it will never be completely ruled out be that due to manufacturing inaccuracies, the axes of the drive shaft and the Piston guide ring are slightly offset from each other (parallel or below a small angle). To compensate for such a misalignment it would be on conceivable, a simple elastic coupling between the drive shaft and the piston guide ring to arrange. However, elastic couplings are usually not able to provide a Compensate for misalignment without force; because the deformation of elastic Links always cause reaction forces, but that of the piston guide ring straight should be kept away. On the other hand, there are couplings with universal joints or splined shaft connections out of the question because of their large space requirements, one will preferably like explained below, a connection designed in the manner of an Oldham coupling Provide between drive shaft and piston guide ring.

In other radial piston machines (e.g. Stiess, "Pump Atlas", Part I, page 75, Fig. 11-14) already known, the drive shaft for itself in the To store housing. However, these known radial piston machines belong entirely to one other genus; because in these the piston guide ring has a surface of rotation as a piston guide surface; it can therefore not be used to transmit torque to or from be used by the drive shaft, but is fixed or runs in its own Storage free in the housing. Consequently, the drive shaft is also used for the purpose of torque transmission connected to the cylinder block. This has the consequence, among other things, that one Force component directed obliquely to its axis acts, the increased wear between the piston and cylinder block. In contrast, the invention has Radial piston machine has a piston guide ring with flat, polygonally arranged Start piston guide surfaces and pistons with flat sliding surfaces Piston shoes as well as a drive shaft non-rotatably connected to the piston guide ring, so that the torque transmission from the drive shaft or on the drive plate by means of that in feature b) The clutch mentioned above can be slipped out via the key guide ring he follows. Only a radial one acts on the individual piston, i.e. exactly in whose axis acting force, so that also the wear between the piston and cylinder block is reduced to the smallest possible amount.

Another decisive advantage achieved by the invention is that the prerequisite is created for the application of a important further idea of the invention (claim 2). After that is the storage of the piston guide ring in the machine housing, as per se also from the "Pump Atlas known, provided directly on its outside. This eliminates the the known radial piston machine according to DT-OS 2 134 944 required lateral Support disks, the production of which (because of the required exact parallelism of the Axes of the cylinder block and the piston guide ring) are carried out very carefully must and is therefore expensive.

Advantageous configurations of the bearing of the piston guide ring in the housing are described in claims 3 to 5. By running as Plain bearings, especially those used to balance the hydraulic system forces Relief pockets, is a particularly low-wear and at the same time low-noise Execution of the machine achieved. It should be noted that the characteristics of claims 2 to 5 only applicable in connection with the features of claim 1 are. That would be in the storage of the described in claims 2 to 5 Piston guide ring, the drive shaft rigidly connected to this, so would be such Storage particularly endangered by forces introduced from outside. Basically but can, according to the invention, the independent storage of drive shaft and piston guide ring can also be used advantageously when the piston guide ring has lateral Support disks is mounted, whereby either both support disks in the housing (according to DT-OS 2 134 944) or at least one of the support disks on the control pin will.

The last-mentioned version is only available for machines with a control pin rigidly inserted in the housing, i.e. with a constant displacement volume applicable per revolution.

If the one used to support the Kelberlfuhrungsringes, im Mating surface located in the machine housing (apart from the relief pockets) extends evenly and without interruptions over the entire circumference, the Supply of pressurized work equipment to the relief pockets according to Claim 6 take place via bores guided radially through the piston guide ring. This design has the advantage that the otherwise from the connecting lines to the ducts leading to the relief pockets can be dispensed with. Making a Line through each piston does not represent any additional effort, because this line is necessary anyway to feed a relief pocket located on the piston shoe. However, in this embodiment, the treads assigned to one another are Plain bearings - because, as mentioned above, they must not have any interruptions - and thus the bearing friction losses are relatively large.

Therefore, this version is preferably used for smaller units in question, at which the maximum circumferential speed in the said plain bearing does not exceed a permissible value.

In contrast, the embodiment described in claim 7 has the advantage that the sliding surfaces of the plain bearing sliding on each other are smaller, which is why this version will be preferred for the larger structural units.

The clutch mentioned in feature b) of claim 1 is useful designed as a so-called Oldham coupling. Such a coupling has a Intermediate piece, which with the two machine parts to be coupled via two radial Slideways is connected, which are offset from one another by 90 °. At acquaintances Couplings of this type are the sliding guides by protruding in the axial direction Processes formed. In contrast, in the machine according to the invention, there is the clutch advantageously designed according to claim 8. The fact that in this version the extensions on the intermediate piece designed as a drive plate and on the Drive shaft protrude not in the axial but in the radial direction, simplified the manufacture of the components forming the coupling; at the same time decreases the overall length of the machine by the axial length of the drive plate, as this on instead of next to the Treiovelle. and therefore does not take up any additional space.

So despite the above-described connection between the drive shaft and Drive plate the latter a safe axial guidance in the direction of the outer Has the end of the drive shaft without a sliding guide between the drive plate and the machine housing must be provided, the features of the Claim 9 and optionally claim 10 applied.

The guide of the piston guide ring in the axial direction is one for small machine units with relatively low maximum circumferential speeds expediently perform according to claim 11. This design has the advantage that the Space requirement in the axial direction is very small. With larger machine units on the other hand, one of the versions according to claims 12 or 13 will be preferred, in which axial sliding guides between the piston guide ring and the housing be avoided. Finally, mixed construction methods are also conceivable in which only one side of the piston guide ring is provided with an end face sliding on the housing is and the axial guide in the direction of the other side via the piston or takes place via the clutch.

Embodiments of the invention are shown below with reference to the drawings described. These show radial piston machines with constant displacement per revolution. However, the features of the invention also apply to radial piston machines with variable displacement, i.e. with radial piston machines with displaceable Control pin (adjustable eccentricity), applicable.

In detail: FIG. 1 shows a radial piston machine in longitudinal section partly along line I-I of Figure 2, partly along line I'-I 'of Figure 3; Fig. 2 shows a cross section according to line II-II of FIG. 2, FIG. 3 shows a cross section according to line III-TII of Figure 1; Fig. 4 is a partial section along line IV-IV of Fig. 3, Fig. 5 shows a radial piston machine which differs from FIGS. 1 to 4 in cross section along line V-V of Figure 6; 6 shows a longitudinal section along line VI-VI of FIG. 5; FIGS. 7 and 8 each show a radial piston machine, which has been modified again compared with FIG. 1, in partial longitudinal section.

In Figures 1 to 4, the parts of a designed according to the invention Radial piston machine characterized as follows: 10 housing; 11 housing cover; 12th Control pin pressed into housing 10; 13 cylinder block, rotatable on the control pin 12; 14 axis of rotation of the cylinder block 13; 15 cylinder spaces in the cylinder block 13; 16 Pistons; 17 piston shoes rigidly connected to the piston 16; 18 relief pockets in the sliding surfaces of the piston shoes 17; 19 holes in the piston 16 for connection the cylinder spaces 15 with the relief pockets 18; 20 piston guide ring; 21 level and piston guide surfaces arranged in a polygonal manner; 22 cylindrical running surface the outside of the piston guide ring 20; 23 counter surface in the housing 10 for Storage of the piston guide ring .20; 24 Housing lining made of wear-resistant Bearing material; 25 axis of rotation of the piston guide ring 20; 26 piston return rings; 27 and 27 end faces on the piston guide ring 20 for its axial guidance on the housing 10 or on the housing cover 11; 28 relief pockets in the counter surface 23; 29 radial bores through the piston guide ring 20 for loading the relief pockets 28 with the pressure of the working medium; 30 drive shaft; 31 rolling bearings for mounting the Drive shaft 30 in the housing cover 11 independently of the piston guide ring 20; 32 Driving plate, as a coupling between drive shaft 30 and piston guide ring 20; 33 radially outwardly projecting extensions of the drive plate 32; 54 to each other parallel sliding surfaces on the extensions 33; 35 recesses on the piston guide ring 20, into which the extensions 33 protrude; 36 bore in the drive plate 32; 37 relative to the extensions 33 by 900 offset recesses in the bore 36 of Drive plate 32; 38 projections projecting radially outward into the recesses 37 the drive shaft 30; 39 Roller bearing inner ring, which is also used for the axial guidance of the Drive plate 32 is used in the direction of the outer end of the drive shaft 30; 40, 41 Control slots in control pin 12; 42, 43 connecting holes from the control slots to the connecting lines (44 and 45, see Fig. 6); e Distance between the axes of rotation 14 and 25 (eccentricity).

In FIG. 2, the one located directly behind the drive plate 32 is Piston return ring 26 omitted. In Fig. 3 there are only four of the nine pistons drawn. As you can see, the flow is internal and radial pressurized radial piston machine. "Inward flow" means that the pistons 16 (in contrast to machines with external flow) on their radially inner face are flowed by the working medium, in other words that the cylinder spaces 15, viewed from the piston 16, are arranged inside. "Radially loaded" means that the passage of the working medium from the fixed housing 10 and the control pin 12 onto the rotating cylinder block 13 and back again (as opposed to axially pressurized machines) takes place in the radial direction.

As can be seen in particular from FIGS. 3 and 4, extends the bearing surface serving for the radial mounting of the piston guide ring 20 23 (called "counter surface" above) des Housing 10 over its entire inner circumference. The two opposite, equal-sized relief pockets 28 are relatively long and narrow. Pressing on the relief pockets 28 with the pressure of the working medium takes place from the cylinder chambers 15 via the through the bores 19 leading through the pistons 19, then via those in the piston shoes 17 provided relief pockets 18 and over the center of the flat sliding surfaces 21 outgoing radial bores 29.

In contrast to the design described above, the design 5 and 6 for mounting the piston guide ring 20 in the housing 10, two separate and opposing "counter laurel surfaces 23a are provided (in the drawing only one of the two is visible). Each of these mating surfaces 23a extends about a quarter of the circumference; accordingly is the one in each counter surface 23a provided relief pocket in the circumferential direction shorter than in Fig. 3 and therefore wider. The pressure is now supplied from the connection lines 44 and 45, respectively from through holes 46 and 47.

The embodiment according to FIG. 7 differs from those previously described in that the guide of the piston guide ring 20a in the axial direction is not takes place directly on the housing 10 and on the housing cover 11, but indirectly via the piston 16 and the cylinder block 13, which - as in Fig. 1 and 6 - with little axial play on the control pin 12 is rotatably mounted. Accordingly is the axial play between the piston shoes 17 and the two in the piston guide ring 20a used piston return rings 26 smaller than in Fig. 1 and 6. The axial Game between the ring 20a and the drive plate 32 is about the same as in Figs. 1 and 6.

Another possible embodiment for the axial guidance of the piston guide ring 20b shows FIG. 8. Here, in contrast to the embodiments described above, this is the case axial play between the ring 20b and the drive plate 32 is kept very small, namely on the one hand by a widened piston return ring 26a and on the other hand by a snap ring 48. The same is for a small axial play between the drive plate 32 and the drive shaft 30 taken care of by the drive plate 32 on the one hand on the roller bearing inner ring 39 and on the other hand on one in the drive shaft 30 inserted snap ring 49 is applied.

Claims (13)

Claims Radial piston machine with internal flow, each with a low-pressure and a high-pressure side Connection line (44, 45) for the work equipment and with one on a control pin (12) rotatably mounted cylinder block (13) in which several distributed around the circumference and in the radial direction displaceable pistons (16) are arranged, and with an in a housing (10, 11) rotatably mounted, flat and polygonal piston guide surfaces (21) having piston guide ring (20) on which the piston (16) is rigid with piston shoes (17) connected to them. gen, wherein the axis of rotation (14) of the cylinder block (13) to the axis of rotation (25) of the piston guide ring (20) is offset or displaceable, furthermore with a Drive shaft (30), which is rotatably connected to the piston guide ring (20), thereby characterized in that a) the drive shaft (30) is independent of the piston guide ring (20; 20a; 20b) is stored in the machine housing (11; 11b), b) that as a connection between the drive shaft (30) and the piston guide ring (20; 20a; 20b) a known per se, any difference in the position of the axes of the drive shaft and the piston guide ring Force-free compensating coupling (32) is provided. 2. Radial piston machine according to claim 1, characterized in that that the piston guide ring (20; 20a; 20b) on its outside directly in the machine housing is stored. 3. Radial piston machine according to claim 2, characterized in that that the piston guide ring (20; 20a; 20b) on its outside a cylindrical Has running surface (22) and with this directly in a corresponding counter-running surface (23; 23a) of the machine housing (10; 10a; 10b) is mounted. 4. Radial piston machine according to claim 3, characterized in that said counter surface (23; coated with a wear-resistant material (24) is. 5. Radial piston machine according to claim 3 or 4, characterized in that that said mating surface (23; / - to compensate for the on the piston guide ring (20; 20a; 20b) acting hydraulic system forces - two diametrically opposed to each other opposite relief pockets (28; 28a), which by the pressure of the Work equipment can be acted upon. 6. Radial piston machine according to claim 5s, characterized in that the counter surface (23) - apart from the relief pockets (28) - evenly extends over the entire circumference, and that from the center of each flat sliding surface (21) of the piston guide ring (20) through this an essentially radial bore (29) is passed, which with one of the respective cylinder space (15) through the Piston (16) and the piston shoe (17) through the conduit (19) in connection stands (Fig. 1 to 4). 7. Radial piston machine according to claim 5, characterized in that the mating surface (23a) in two d-, am.efilan opposing circular edges Subareas each with a relief pocket (28a) is divided, and that the relief pockets with the pressure via channels (46, 47) going out from the connection lines (44, -45) of the working medium can be acted upon (Fig. 5 and 6). 8. Radial piston machine according to one of claims 1 to 7, characterized characterized in that the between the piston guide ring (20; 20a; 20b) and the drive shaft (30) arranged coupling has a drive plate (32), which with two on her Perimeter diametrically arranged projections (33), the mutually parallel side surfaces 34) have as sliding surfaces, in corresponding recesses (35) of the piston guide ring (20; 20a; 20b) engages and the further two at an inner disk bore (36) to the outer extensions (33) by 900 offset recesses (37) with parallel Has walls as sliding surfaces, in the corresponding on the circumference of the drive shaft (30) provided projections (38) engage. 9. Radial piston machine according to claim 8, characterized in that that on the drive shaft (30) immediately next to the extensions (38), namely on the axially outwardly directed side of which a ring (39) is arranged, the outer diameter of which is larger than the diameter of the bore (36) of the drive plate (32). 10. Radial piston machine according to claim 9, characterized in that that the ring (39) through the board of a roller bearing inner ring of the bearing of the drive shaft (30) is formed. 11. Radial piston machine according to one of claims 1 to 10, characterized characterized in that the piston guide ring (20) in the axial direction to both Sides out over a flat end face (27, 27?) In the housing (10, 11) is (Figs. 1 and 6). 12. Radial piston machine according to one of claims 1 to 10, characterized characterized in that the piston guide ring (20a) over the piston shoes (17), preferably by means of the piston return rings (26) comprising the piston shoes, as well as via the piston (16) and the cylinder block (13) is guided in the axial direction (Fig. 7). 13. Radial piston machine according to one of claims 1 to 10, characterized characterized in that the piston guide ring (20b) in the axial direction over the Coupling connecting the drive shaft (30j to the piston guide ring (20b), e.g. via the drive plate (32) is guided (Fig. 8). L e r s e i t e