EP1062426B1 - Radial piston engine with guide rollers - Google Patents

Description

The present invention relates to a radial piston motor with roller guides for the axial guidance of the rollers over which the pistons are located Support the cam ring.

From US-A-5081906 (GB-B-2238086) is a the preamble of the claim 1 corresponding radial piston motor known to the task was based on the previously in connection with the axial positioning of the roles associated production engineering effort and thus reduce manufacturing and assembly costs. This task should can be solved by the fact that in the spaces between the roller end faces and the inner surface of the cylinder as a roller guide each has a wedge piece with a viewed in the stroke direction of the piston, arranged in the form of a segment of a circle which is the roller axially opposite the cam ring in the cylinder positioned. The wedge pieces disclosed in the above publication can essentially be divided into three different types.

In a first design, each wedge piece has the one facing the roll A flat surface lying on the front side of the roll and on the side facing away from the roller, the inner surface of the cylinder contacting cylindrical surface. This wedge is also in the Space taken up between the roller, piston and inner surface of the cylinder without to be firmly connected to any of these components. by virtue of opposite this freely movable arrangement of the wedge piece in the piston stroke direction the piston takes the wedge pieces in a load stroke Towards the cam ring with. There is still no contact between the wedge pieces and the cam formed on the cam ring. In the subsequent The idle stroke of the piston, on the other hand, hits the wedge pieces against those on the stroke ring trained cams. This constant butt contact between the cams and the wedge pieces as well as the friction occurring between them can heavy wear on the wedge pieces. Another disadvantage of this Design is that the width of the cam ring must be at least as large that the cam ring in addition to the roller also a contact surface for the two laterally arranged wedge pieces provides. Apart from a high overall weight the radial piston motor results in a wide cam ring as a result the higher manufacturing costs in connection with the Precision machining of the cam ring in high manufacturing costs.

In a second design, each of the two wedge pieces on the Roll facing side on a driver-like projection, which is in a recess provided on the piston between piston and roller in Extends towards the other wedge piece. Because the wedge pieces in this case taken from the roller back into the cylinder when the piston is idle can therefore not be a shock contact come between the wedge pieces and the cams. as a result of high relative speed between the roller and the driver-like Projections of the wedge pieces that contact the outer circumference of the roller, However, there can be high abrasion on the driver-like projections come. With increasing wear of the driver-like projections the wedge pieces could move in the piston stroke direction finally enlarge such that there is a butt contact between the Wedge pieces and the cam could come up. Another disadvantage of this Type is that on the roller guides driver-like projections and Piston recesses need to be formed, which increases manufacturing costs and thus increases the manufacturing costs.

In addition, the friction between occurs in the two types above the roller and the wedge pieces on the entire end face of the roller on. This relatively large-area friction contact requires precision machining the friction surfaces of both components, which again results in high manufacturing costs results.

So far it has also been assumed that as a result of the constant Contact of the rollers with the cam ring, the rollers and thus the respective Piston automatically a certain rotational position in the cylinder or opposite receive the cam ring, what a reliable operation of the radial piston motor is crucial. In certain cases, such as the First start-up of the radial piston engine, in which the cylinders hydraulic fluid is supplied for the first time, however, that the pistons and thus the rollers are immersed so far in the respective cylinder are that a contact between rollers and stroke curve is not yet Is given To the required rotational position of the piston in these cases According to a third design, one of the two has to ensure cylinders Wedge pieces on the side facing the inner surface of the cylinder an elongated Slip into a screw, clamp that goes through the cylinder wall or the like engages and in this way a rotation of the Prevents piston in the cylinder and thus the roller against the cam ring. However, the formation of the groove causes a weakening of the relevant one Wedge piece and thus a shortening of the life of the while the operation of the radial piston motor wedge piece. moreover finds the sliding contact between the wedge piece and the screw or Brackets instead of what appears to be disadvantageous in terms of good role management. Such a constructive measure also means a high level Production expense.

DE-A1-4421535 discloses a roller tappet for a radial piston pump. The roller plunger includes a roller shoe in which a roller is positively guided, via which the roller tappet on a cam ring There is a holding element in to fix the role on the roller shoe Form of a cage holder encompassing the role. The holding element is composed, for example, of two end plates, each are held on the roller shoe by means of unwinding and on the side connecting elements running on the roller, which fix the roller. In another The embodiment is the holding element via two end plates and thus connected bends held on the roller shoe, the role on the face side with two guide pins arranged centrally to the longitudinal axis of the roller is provided, which protrude into recesses in the face plates. In DE-A1-4421535, however, is no indication that the Roll each axially on the end elements arranged on the end support the inner wall of the cylinder.

In view of those found in conventional radial piston motors Disadvantages of the object of the present invention are therefore to create a technically optimized radial piston motor that stands out a low manufacturing outlay and at the same time a reliable function Operation distinguished.

This object is achieved by the subject matter according to the invention solved the features of claim 1, in particular is characterized in that the arranged on the end faces of the rollers Roller guides are fixed in the piston stroke direction with the respective roller are connected.

Since the roller guides in the piston stroke direction, i.e. both during of the load stroke as well as during the empty stroke, taken from the respective role the roller guides can be sized in this way that they do not protrude beyond the outer circumference of the role, so that no between the roller guides and the cam ring Butt contact takes place This ultimately leads to an increase in the service life of the roller guides and thus for reliable operation of the radial piston motor as a whole Roller guides material saved.

If the roller guides do not come into contact with the cam ring, the width of the cam ring can also be reduced to a width that corresponds at most to the width of the rolls. In this way it is disregarded of the total weight of the radial piston motor also the manufacturing technology Effort and thus the manufacturing costs with regard to precision machining the stroke curve of the stroke ring is significantly reduced.

Through suitable design measures, for example through the Formation of a cylindrical projection on the roller guide, which in a corresponding recess is inserted on the front side of the roll, the relative speeds at the friction surfaces of Reduce the roller and roller guides and thus wear on both components. Due to the reduced wear, even after a long period of operation minimal play between the roller and roller guides held. This contributes to functionally reliable and reliable operation of the radial piston motor as a whole.

Further advantageous features of the radial piston engine according to the invention are the subject of the subclaims.

The connection of the roller and roller guides that is fixed in the stroke direction can be implemented through simple manufacturing measures. For example, the roller guides on the front of the Roll facing side have a cylindrical projection which in a central, cylindrical recess formed on the end face of the roller can be used. It would of course also be conceivable that the Roller guides on the side facing the end of the roller Have recess in which a formed on the end face of the roller Lead can be used. The recess and the one with the recess in However, the protruding engagement could also be conical. If the diameters of the recesses and the projections are dimensioned that they are small compared to the outside diameter of the roll, i.e. that the projections and the recesses are centered on one Focus the area around the axis of rotation of the reel, and face the protrusions engaging with the respective recesses in such a way that between the ring surface of the roller around the recess and the surface around the The lead of the roller guide is a game, decrease in the Operation of the radial piston motor on the outer periphery of the projection and peripheral speeds present on the inner peripheral wall of the recess and thus the relative speed between Role and roller guides. Because they are also spaced apart on the two Surfaces of the roller and roller guide no friction occurs, one will Reduction of frictional abrasion achieved on both components.

The surfaces of the roller guides contacting the inner surface of the cylinder are preferably cylindrical for the sake of simplicity, which ensures optimal guidance of the piston-roller arrangement in the cylinder is achieved. Since the roller normally does not have any compressive loads in the axial direction experienced, it would also be conceivable that on the inner surface of the cylinder adjacent surface of the roller guide with respect to the axis of rotation of the To form a role rotationally symmetrical or spherical segment. In this The case would even be one in the stroke direction of the piston as well as in the direction of rotation the role fixed connection between roller guide and role possible. This would have the advantage that in the operation of the radial piston motor between Roller and roller guides no longer occurs and the between The friction of the roller guide and the inner surface of the cylinder is considerable is reduced.

So far, it was assumed that the role with the stroke curve of the cam ring is in contact, causing the rotational position of the piston in the cylinder and accordingly the alignment of the roller with respect to the stroke curve is automatically specified. As mentioned at the beginning, However, it can also happen that the contact between the role and The cam ring breaks off. In this case, according to the present invention by means of an anti-rotation device arranged separately from the roller guide prevents rotation of the piston in the cylinder and thus a certain one Alignment of the roller with respect to the cam ring are observed.

For this purpose, the piston can on the side facing away from the roller End section one perpendicular to the axis of rotation of the cylinder block have aligned flattening on a corresponding contact surface the anti-rotation is applied, whereby the rotational position of the piston in Cylinder and the roller against the stroke curve is clearly specified. An effective measure has also been found when the cylinder at least two cylinder sections of different inner diameters and the piston accordingly at least two piston sections of different, diameter adapted to the corresponding cylinder diameters having. In this case, the anti-rotation device is in the cylinder section the smaller inner diameter and the flattening accordingly on Piston section provided with the smaller diameter. Through this The measure will be a large area of pressure on the piston preserved and on the other hand only little to form the flattening Material removed from the piston. The additional anti-twist device creates compared to the conventional anti-rotation device mentioned at the beginning better guidance of the piston in the cylinder, since according to the present Invention a large-area sliding contact between the piston and anti-rotation takes place.

The anti-rotation device preferably has one in the stroke direction of the piston viewed, circular segment-shaped cross section with one of the cylinder inner surface corresponding arc and one corresponding to the flattening Tendon.

Because the cylinder block usually has axial access holes anyway has, via which the hydraulic fluid reaches the respective cylinder spaces, can the production engineering effort in terms of fixing the Reduce the anti-twist device in the cylinder by using the anti-twist device is fixed in the cylinder by means of a pin that goes over the access hole inserted into a blind hole in the cylinder block aligned with the access hole becomes.

Fig. 1 einen Längsschnitt einer bevorzugten Ausführungsform des erfindungsgemäßen Radialkolbenmotors;

Fig. 2 einen Querschnitt durch den Zylinderblock in Fig. 1 entlang der Linie II-II;

Fig. 3a einen in größerem Maßstab dargestellten Schnitt durch den Zylinderblock in Fig. 2 entlang der Linie III-III;

Fig. 3b eine Perspektivansicht des Kolbens;

Fig. 4 einen Schnitt durch den Zylinderblock entlang der Linie IV-IV in Fig. 1;

Fig. 5 eine Perspektivansicht der Rollenführung;

Fig. 6 einen Schnitt durch den Zylinderblock entlang der Linie VI-VI in Fig. 1;

Fig. 7 eine Perspektivansicht der Verdrehsicherung;

Fig. 8a und 8b Abwandlungen der Rollenführung in Fig. 5;

Fig. 9a und 9b Abwandlungen der Verbindung zwischen Rollenführung und Rolle in Fig. 5; und

Fig. 10a und 10b Abwandlungen des Zylinderblocks in Fig. 3a.

Further features and advantageous embodiments of the present invention will become apparent from the following description of the preferred embodiment with reference to the drawing. It shows

1 shows a longitudinal section of a preferred embodiment of the radial piston engine according to the invention.

FIG. 2 shows a cross section through the cylinder block in FIG. 1 along the line II-II;

3a shows a section through the cylinder block in FIG. 2 along the line III-III shown on a larger scale;

3b is a perspective view of the piston;

4 shows a section through the cylinder block along the line IV-IV in Fig. 1.

Fig. 5 is a perspective view of the roller guide;

6 shows a section through the cylinder block along the line VI-VI in Fig. 1.

7 is a perspective view of the anti-rotation device;

8a and 8b modifications of the roller guide in Fig. 5;

9a and 9b modifications of the connection between roller guide and roller in Fig. 5; and

10a and 10b modifications of the cylinder block in Fig. 3a.

Referring now to Figures 1-6, a preferred one will now be given Embodiment of the radial piston engine according to the invention described. The radial piston motor 2 consists essentially, as shown in Fig. 1 from two housing parts 4 and 6 and one between the two Housing parts 4 and 6 arranged cam ring 8. The two housing parts 4 and 6 and the cam ring 8 are coaxial and fluid-tight by means of screws 10 screwed together. On the inner surface of the lifting ring 8 is a lifting curve 12 formed with a plurality of cams 14, as is special can be seen in Fig. 2.

Within the cam ring 8 is a around a longitudinal or rotational axis 16 arranged rotatably arranged cylinder block 18. As in Figs. 1 and 2 can be seen, the cylinder block 18 has an internal toothing central recess 20 on. In this recess 20 is a End section 22 of an output shaft 24, with one of the internal teeth the recess 20 corresponding external teeth is provided axially slidably added. The output shaft 24 is via a bearing 30 rotatable relative to the two housing parts 4 and 6 and the cam ring 8 stored. The bearing 30 comprises two tapered roller bearings 32 and 34 which in the Housing part 4 are housed and transmit high axial and radial forces can. The other end section 26 protruding from the housing part 4 the output shaft 24 has a shaft flange 28 for attachment to a Not shown drive element of a device to be driven, for example on a wheel of a loader.

In the cylinder block 18 there are also a plurality of with respect to the Rotation axis 16 star-shaped radially outwardly directed cylinder 36 with a cylindrical axis 37 perpendicular to the axis of rotation 16. As can be seen in the enlarged illustration in FIG. 3a, the cylinder has 36 a cylinder section lying radially outside with respect to the axis of rotation 16 38 with a large inside diameter and a radially inside lying cylinder section 40 with a small inner diameter on. The cylinder section 38 stands on the substantially cylindrical outer peripheral surface 42 of the cylinder block 18 open. Furthermore is in the cylinder block 18 a parallel to the longitudinal or rotational axis 16, in the cylinder section 40 opening bore 43 formed, through which in operation of the radial piston motor 2 hydraulic fluid is supplied or discharged.

A piston 44 is received in the cylinder 36 which, as shown in FIG. 3b is shown has piston sections 46 and 48. Piston section 46 has a diameter that is essentially the inner diameter of the Cylinder section 38 corresponds. The piston section 48 has on its The outer circumference has two flats 48a and 48b, which, as shown in FIG see is aligned perpendicular to the axis of rotation 16. The diameter the outer circumference of the piston section 48 corresponds to the inner diameter of the cylinder section 40. The flattened portion 48b defines a contact surface, the one on a correspondingly provided contact surface 50b Anti-rotation lock 50 described in more detail below is present. The flattened portion 48a faces the access bore 43.

If the cylinder 36 in the operation of the radial piston motor 2 via the Access bores 43 are supplied with hydraulic fluid, the pistons 44 selectively pressurized in such a way that it has a lifting movement run towards the cam ring 8. They support each other a corresponding roller 54 on the lifting curve formed on the lifting ring 8 12 from. As shown in Fig. 1, the axial width B corresponds to the Hubrings in this embodiment of the radial piston motor 2 essentially the axial length of the rollers 54. On the one facing the cam ring 8 A bearing 56 is formed in the end section of the respective piston sections 46, in which the respective roller 54 relative to the piston 44 by one Rotation axis 58 is rotatably supported.

As shown in Figures 1, 3a, 4 and 5, is on each of the two A roller guide 60 is arranged on the end faces 54a and 54b of the roller 54, whereby the axial position of the roller 54 in the cylinder 36 and thus opposite the piston 44 and the stroke curve 12 is predetermined. The roller guides 60 are each in one of the ends 54a or 54b of the roller 54, the piston 44 and the cylinder inner surface of the cylinder 36 trained rooms arranged. Fig. 5 shows a perspective view of the Roller guide 60, viewed in the piston stroke direction, essentially one has circular segment-shaped cross section. At the front 54a or 54b of the tendon side facing the roller 54 has each roller guide 60 has a cylindrical projection 62 that is axial with respect to the axis of rotation 58 on that with a corresponding central recess 54c or 54d the end faces 54a and 54b of the roller 54 is engaged. The cylindrical Bow side 63 of each roller guide 60 lies on the inner surface of the cylinder Cylinder 36. The length of the axial projection 62 is slightly larger than the depth of the recess 54c or 54d, so that between the surface of the Roller guide 60 around the central projection 62 and each ring surface the end face 54a or 54b of the roller 54 around the central recess 54c or 54d there is a game.

By the way of connecting the roller guides described above 60 with the roller 54, the roller guides 60 in the operation of the Radial piston motor 2, i.e. with a stroke movement of the pistons, in the piston stroke direction taken away from the respective roll 54. Because as above described the width of the cam ring corresponds to the length of the rollers in operation of the radial piston engine according to this embodiment, independently whether the roller guides in the piston stroke direction over the roller protrude, no butt contact between the roller guides and the Lifting ring instead. In addition, the wear of both components due to the im Operation of the radial piston motor occurring relative speed between Reduce roller guides and roller considerably, since the friction between the two components occur in an area in which the relative speed is relatively low.

As can be seen in FIG. 6 and has already been mentioned above, is on the cylinder inner surface of the cylinder section 40 opposite the access bore 52 a so-called anti-rotation device 50 is provided, which Function has a rotation of the piston 44 in the cylinder 38 about a cylinder axis 37 to prevent. The key here is that a certain Rotational position of the piston 44 with respect to the cylinder axis 37 and thus the Roll 54 is maintained with respect to the stroke curve 12. The anti-rotation device 50 is a cylinder pin by means of a pin 76, for example a taper pin or grooved pin attached to the cylinder block 18 in the manner as it is shown in Fig. 3a or Fig. 6. Fig. 7 shows a perspective view of the Anti-rotation device 50, like the roller guide 60, in the piston stroke direction considered, has a substantially circular segment-shaped cross section, the cylindrical arc side 50a on the cylinder inner surface of the Cylinder section 40 and the chord side 50b on the piston section 48 of the piston 44 formed flattened portion 48b. In contrast to Roller guide 60, which in this embodiment of the radial piston motor has a projection 62, in the anti-rotation device 50 is a cylindrical Recess 78 formed in which the part of the pin 76 is seated, which is made of the blind hole 84 in the cylinder block 18 aligned with the access hole 43 protrudes.

A fluid control is represented by reference numeral 66 by means of the hydraulic fluid in operation of the radial piston motor 2 via the access holes 43 fed to the respective cylinder rooms or from the respective Cylinder rooms is discharged. The fluid control 66 is in the housing part 6 arranged fluid-tight and non-rotatable. To the hydraulic fluid to the respective To be able to distribute cylinder spaces, the fluid control 66 has two of them separate circumferential grooves 68 and 70, each with a Fluid channel 72 or 74 are connected. In the operation of the radial piston motor 2, the fluid channels 72 and 74 alternate with the axial access bores 43 in connection, which are formed in the cylinder block 18 and each communicate with one of the cylinder rooms.

In the operation of the radial piston engine 2, the pistons 44 are over the Fluid channels 68, 70, 72 and 74, the access holes 43 and the cylinder spaces controlled by means of hydraulic fluid such that they are with respect to the axis of rotation 16 are pressed radially outwards. They support themselves over it the respective roller 54 on the cam 12 of the cam ring 8, whereby the Finally, cylinder block 18 rotates about axis of rotation 16 is initiated. The direction of rotation is selected by the control method. Via the positive connection of the output shaft 24 with the cylinder block 18, a torque is transmitted to the output shaft 24. This supports from the tapered roller bearings 32 and 34 of the bearing 30. A drive element for example a wheel of a not shown here Loader, which is connected to the output shaft 24 via the flange section 28 is given a torque.

Figures 8a and 8b show modifications of the context with the above embodiment of the radial piston engine according to the invention described roller guides.

The roller guide 90 shown in Fig. 8a differs from that 5 roller guide 60 shown in that it on the lifting ring 8th facing upper outer surface corresponding to the outer circumference of the roller 54 is rounded and designed in such a way that it is in the piston stroke direction does not protrude beyond the outer circumference of the roll. Because the roller guide 90 does not protrude beyond the outer circumference of the roller 54 in this case and also in the piston stroke direction in a manner fixed against displacement with the roller 54 stands, the roller guide 90 - of course, only together with the Roller 54 according to the invention also for a conventional radial piston motor be used with a cam ring, the cam ring one Has a width which is greater than the length of the roller 54.

While the surfaces 63 contacting the cylinder inner surface the roller guides 60 previously cylindrical for simplicity the roller guide 92 shown in FIG. 8b has on the inner surface of the cylinder facing side with respect to the axis of rotation 58 of the roller 54 rotationally symmetrical or spherical segment-like surface 93. Since the Roller and thus also the roller guides in the operation of the radial piston motor should not normally experience excessive axial loads a spherical segment-like design of the roller guides does not become one Reduce the lifespan of the roller guides. To in this Case to constantly achieve a reliable axial positioning of the rollers, However, it is necessary that the pistons during operation of the radial piston motor only be raised so far that the axis of rotation 58 of each roller 54 is is still inside the cylinder even at maximum piston stroke. This limitation is with the roller guides mentioned above not necessary due to the large area contact.

In the special case shown in Fig. 8b, the roller guides could 92 not only in the piston stroke direction but also in the direction of rotation of the Roller 54 are positively and / or non-positively connected to roller 54, so that there is no more friction between roller and roller guide. As a result of the small, essentially only linear arrangement of the roller guide 92 on the inner surface of the cylinder would also be that between the roller guide 92 and the inner surface of the cylinder considerably reduced. Since the roller guides 90 and the roller 54 are then no longer relative to each other could rotate, the positive and / or non-positive connection between roller guide and roller in any other way and Way to be realized. It would also be conceivable the role and the role guides to be formed in one piece, i.e. to provide the roller guides on the roller.

Figures 9a and 9b show further possibilities, the roller guides to relate to the role.

While in the preferred embodiment described above of the radial piston motor 2 according to the invention on each roller guide a projection 62 and corresponding recesses on the roller 54c and 54d were formed, the roller guide 94 according to FIG. 9a a recess 95 and the roller 96 a corresponding projection 97 on. In this example, too, is between the opposite surfaces on roller guide and roller around the recess or the projection a game exists, which causes the occurring between these components Friction occurs in an area where small relative speeds prevail between roller and roller guides. However, the present one Invention not only limited to this; of course it would also be possible that the roller guides in the conventional sense, i.e. without play, immediately to be in contact with the role.

The roller guide 98 in Fig. 9b is characterized by a conical Projection 99 from that with a corresponding, conically shaped, centric Recess 101 is engaged on the roller 100. In this case the roller guide engages with the roller without play, however, as in the previous examples, the contact area between Roller 100 and roller guides 98 in one with respect to the axis of rotation 58 central area is relocated.

In the preferred embodiment, an anti-rotation device is 50 provided that a rotation of the piston 44 in the cylinder 36 and thus the roller 54 against the stroke curve 12 prevented. However, since the roles normally in constant contact with the stroke curve, causing the Rotational position of the roller and thus the piston is determined automatically, it is it is not absolutely necessary to provide an anti-rotation device. This case is shown in Figure 10a. Here the cylinder and piston construction is simplified essential, since neither on the piston 102 nor on the cylinder block production-related Measures must be taken.

However, another relatively simple constructive one can also Measure on the piston and cylinder block, as shown, for example, in FIG. 10b an anti-rotation device 106 for the piston 104 is shown, without piston and cylinder having to be graduated.

At this point it should be noted that all of the above Features, especially in connection with the design the roller guide, the connection between roller guides and roller like also the anti-rotation device for the piston - if technically possible - with each other can be combined.

The present invention thus creates a technically optimized Radial piston motor with a cam ring and one opposite the cam ring Cylinder block with a multiplicity arranged rotatably about an axis of rotation of cylinders aligned in the radial direction of the cylinder block. In the Each cylinder has a piston that can be moved in the radial direction, which is supported by a roller on the cam ring. The role is in one Piston provided storage about a to the axis of rotation of the cylinder block parallel axis of rotation rotatably supported and supported on its front sides arranged roller guides with respect to their axis of rotation in the cylinder axially. The radial piston engine according to the invention is particularly notable characterized in that the roller guides in the piston stroke direction with the each role are connected to move and accordingly with both a load stroke and an empty stroke of the piston in the piston stroke direction be taken away from the respective role, so no Contact of the roller guides with the cam ring takes place.

Claims (11)

1. A radial piston engine (2) with a cam ring (8), a cylinder block (18) disposed to rotate relative to the cam ring (8) around an axis of rotation (16), the said block having a plurality of cylinders (36) aligned in radial direction of the cylinder block (18), in each of which cylinders there is accommodated a slidable piston (44), which is braced via a roller (54, 96, 100) against the cam ring, wherein the roller is mounted on the piston to rotate around an axis of rotation (58) parallel to the axis of rotation (16) of the cylinder block (18) and, relative to its axis of rotation (58), is braced axially in the cylinder (36) via roller guides (60, 90, 92, 94, 98) disposed at its end faces, characterized in that
   the roller guides (60, 90, 92, 94, 98) are rigidly connected to the respective roller (54, 96, 100) with respect to sliding in piston displacement direction.
2. A radial piston engine according to claim 1, characterized in that the roller guides (60, 90, 92, 98) are provided on the side facing the end face of the roller (54, 100) with a projection (62, 99), which is insertable into a recess (54c, 54d, 101) formed on the end face of the roller.
3. A radial piston engine according to claim 1, characterized in that the roller guides (96) are provided on the side facing the end face of the roller (96) with a recess (95), into which a projection (97) formed on the end face of the roller is insertable.
4. A radial piston engine according to one of claims 1 to 3, characterized in that the roller guides (60, 90, 94, 98) have on the side facing away from the end face of the roller a cylindrical surface corresponding to the cylindrical inside surface.
5. A radial piston engine according to one of claims 1 to 3, characterized in that the roller guides (92) have on the side facing away from the end face of the roller a surface which is rotationally symmetric or has the form of a spherical segment relative to the axis of rotation (58) of the roller.
6. A radial piston engine according to claim 5, characterized in that the roller guides (92) are connected with the roller to rotate therewith in the direction of rotation of the roller.
7. A radial piston engine (2) according to one of the preceding claims, characterized by an antirotation device (50), disposed separately from the roller guides, to prevent turning of the piston in the cylinder.
8. A radial piston engine according to claim 7, characterized in that the piston is provided on the end portion facing away from the roller with a flattened part, which bears on a corresponding contact face of the antirotation device.
9. A radial piston engine according to claim 8, characterized in that the cylinder is provided with at least two cylinder portions (38, 40) of different diameters and the piston is provided accordingly with at least two piston portions (46, 48) of different diameters matching the corresponding cylinder diameters, the antirotation device being provided in the cylinder portion (40) with the smaller inside diameter and the flattened part being provided on the piston portion (48) with the smaller diameter.
10. A radial piston engine according to claim 9, characterized in that the antirotation device has a cross section which, viewed in piston displacement direction, is a circular segment, with an arc corresponding to the cylindrical inside face and a chord corresponding to the flattened part.
11. A radial piston engine according to one of claims 7 to 10, characterized in that the antirotation device is fixed to the cylindrical inside face of the cylinder portion (40) with the smaller diameter by means of a pin (76), which is inserted via an inlet port (43) for supply and removal of hydraulic fluid in the cylinder space, the pin (76) being fastened in an opening (84) in the cylinder block (18) aligned with the inlet port (43).

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