Radial piston compressor, mounting sleeve, and method for assembling a piston assembly

Abstract

The present invention relates to a radial piston compressor comprising a compressor unit (1) and a drive device (2) for driving the compressor unit, wherein the compressor unit (1) comprises a plurality of piston-working chamber combinations (13) arranged radially around an eccentric shaft (11, 12) with an axis of rotation (D), wherein the piston-working chamber combination (13) comprises a working chamber (131) and a piston (132) displaceable therein, wherein the piston (132) comprises a piston ring (134) which is received in a circumferential piston ring groove (1321) of the piston, wherein the piston ring (134') is provided with at least one chamfer (1341) on its outer circumference. Furthermore, the invention relates to a mounting sleeve with a negative geometry, as well as a method for mounting a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor.

Description

[0001] The present invention relates to a radial piston compressor according to the preamble of claim 1, a mounting sleeve according to the preamble of claim 7, and a method for mounting a piston assembly according to claims 10, 12, 13 and 14.

[0002] A radial piston compressor is a component of fluid power technology. In contrast to an axial piston compressor, in this type of compressor at least one piston-working chamber combination is arranged radially and perpendicular to the drive shaft. A radial piston compressor can also be referred to as a compressor based on the radial piston principle.

[0003] The piston's conveying or reciprocating motion is usually generated by an eccentric. Therefore, the drive shaft with the eccentric can also be referred to as an eccentric shaft. A radial piston compressor typically comprises several piston-working chamber combinations radiating outwards from the eccentric shaft in a star-shaped pattern.

[0004] A piston-working chamber combination essentially comprises a working chamber, also called a cylinder, and a piston that moves up and down within the working chamber. The piston has a central geometric axis that coincides with the piston's direction of movement. In a radial piston compressor with an eccentric shaft, the piston has a contact surface on the side facing the eccentric shaft. During the rotation of the eccentric shaft, the eccentric disk contacts or rests against this surface. The eccentric shaft has an axis of rotation around which it rotates. When the eccentric disk contacts the contact surface, the piston moves upward, compressing the medium in the working chamber.

[0005] Radial piston compressors are used, for example, to compress refrigerant in the air conditioning systems of motor vehicles, especially in electric vehicles. A refrigerant such as CO2 can be used as the medium to be compressed. However, other media and refrigerants are also conceivable.

[0006] A radial piston compressor of the aforementioned type is known, for example, from DE 10 2020 211 680 A1 or from the applicant's patent application DE 10 2022 133 723 A1, which was unpublished at the time of this application.

[0007] Typically, the pistons are sealed to the cylinder wall of the cylinder housing by a piston ring positioned within the piston. The piston ring improves the sealing function and thus the efficiency of the compression and therefore of the entire compressor.

[0008] The working chamber(s) of a radial piston compressor are typically equipped with or interrupted by milled pockets. This means that, as assembly progresses, the piston ring is at risk of shearing off at the edges of these milled pockets. This problem is exacerbated by the fact that, due to functional requirements, the piston ring's outer diameter is usually larger than the piston diameter.

[0009] The present invention addresses this issue and aims to propose a radial piston compressor that is easy to assemble. In particular, a radial piston compressor is proposed whose pistons can be mounted in the working chambers, thereby minimizing the risk of piston ring shearing during assembly.

[0010] According to the invention, this problem is solved by a radial piston compressor with the characterizing features of claim 1.

[0011] By providing the piston ring with at least one chamfer on its outer circumference, the risk of shearing during assembly can be minimized. In other words, a fundamental aspect of the invention is to provide a chamfer on at least one side of the piston ring's outer surface to prevent damage to the critical edges when the piston ring is inserted into the working space.

[0012] Further advantageous embodiments of the proposed invention arise in particular from the features of the dependent claims. The subject matter or features of the various claims can, in principle, be combined with one another in any way.

[0013] In an advantageous embodiment of the invention, the at least one chamfer can be configured as a chamfer on a circumferential outer edge of the piston ring. The originally, usually right-angled, edge of the piston ring is accordingly replaced by a chamfer. This results in the desired chamfer, which can counteract shearing of the piston ring when the piston is inserted into the working chamber.

[0014] In a further advantageous embodiment of the invention, the piston ring can be provided with two chamfers, each located on the two circumferential outer edges of the piston ring. This can, in particular, prevent incorrect installation in series production.

[0015] In a further advantageous embodiment of the invention, the piston ring can be designed as a closed or slotted piston ring, particularly with variations in the slot / groove geometry. A piston ring without a slot is the preferred variant with regard to sealing performance, since no gas can escape from the compression chamber through the groove / gap. However, the slotted variant is more challenging for mounting the piston ring to the piston, as the ring must be stretched considerably to fit it to the piston.

[0016] In a further advantageous embodiment of the invention, the working space can be provided with at least one milling pocket, wherein the height of the piston ring is greater than the maximum milling pocket depth. For assembly, the higher the piston ring, the better. The aim should be to design the height of the piston ring to be greater than the maximum milling pocket depth in the cylinder head. Preferably, a simple cylindrical mounting sleeve can then be used to further facilitate assembly.

[0017] In a further advantageous embodiment of the invention, the piston ring can be designed as a piston ring made of polytetrafluoroethylene (PTFE), in particular as an unslotted PTFE ring. PTFE has particularly good sliding properties, which reduces the friction of the ring and thus the losses, without impairing the sealing effect.

[0018] Another object of the present invention is to propose an advantageous mounting sleeve for mounting a piston assembly into the working space of a radial piston compressor according to the invention, wherein the working space comprises a cylinder wall.

[0019] According to the invention, this problem is solved by a mounting sleeve with the characterizing features of claim 7. By providing the mounting sleeve with at least one negative geometry, an advantageous aid for facilitating the assembly of the piston assembly into the working chamber of the radial piston compressor can be provided.

[0020] In particular, when assembling the piston assembly in the working space, the piston ring can be guided through the mounting sleeve until it enters the working space below a critical edge of the at least one milling pocket.

[0021] Advantageously, the negative geometry can be designed as the inverse geometry of a milled pocket in the cylinder wall. In other words, the negative geometry can, for example, be designed as the inverse geometry of steps, shoulders, recesses, or the like, forming an edge against or within the cylinder wall. This preferably results in a positive fit between the milled edge and the negative geometry.

[0022] Another object of the present invention is to propose an advantageous method for mounting a piston in a working chamber of a radial piston compressor according to the invention.

[0023] According to the invention, this problem is solved by a method according to claim 10. By pre-assembling the piston ring onto the piston to be inserted into the working chamber, and by inserting the piston with the piston ring as a piston assembly into the working chamber, with the piston being inserted into the working chamber with the chamfer of the piston ring leading, there is a reduced risk of the piston ring being sheared or destroyed by milled edges of the working chamber. The chamfer forms a kind of leading edge, which pushes the piston ring back towards the piston ring groove as it passes over the leading edge, thus allowing the piston ring to pass through undamaged.

[0024] Further advantageous embodiments of the proposed invention arise in particular from the features of the dependent claims. The subject matter or features of the various claims can, in principle, be combined with one another in any way.

[0025] In an advantageous embodiment of the invention, the piston assembly can be inserted into the working chamber from the outside in. This means that the piston is inserted into the working chamber in the direction of the eccentric shaft. Typically, the piston ring is located in the area of ​​the piston head, so that a large portion of the piston is already contained within the working chamber and guides the piston accordingly before the piston ring reaches the critical areas, particularly milling pockets. Alternatively, the piston assembly can also be inserted into the working chamber from the inside out.

[0026] The invention further relates to an advantageous method for assembling a piston assembly, comprising a piston with a piston ring, in a working chamber of a radial piston compressor using an assembly sleeve. The working chamber into which the piston assembly is to be mounted is equipped with at least one milled pocket, wherein the milled pocket has a milled pocket depth measured from the cylinder head surface, and wherein the piston ring has a height, the height of which is greater than the maximum milled pocket depth. During the assembly of the piston assembly in the working chamber, the piston ring is guided through an assembly sleeve until it enters the working chamber below a critical edge of the at least one milled pocket.

[0027] The invention further relates to another advantageous method for mounting a piston assembly, comprising a piston with a piston ring, in a working chamber of a radial piston compressor. The working chamber into which the piston assembly is to be mounted is equipped with at least one milled pocket, and in particular with more than one milled pocket. A mounting sleeve, which is provided for inserting the piston assembly, has at least a partial negative geometry corresponding to the arrangement of the milled pockets in the working chamber.

[0028] The invention further relates to another advantageous method for mounting a piston assembly, comprising a piston with a piston ring, in a working chamber of a radial piston compressor. The working chamber into which the piston assembly is to be mounted is equipped with at least one milled pocket, and in particular with more than one milled pocket. A mounting sleeve, which is provided for inserting the piston assembly, has two protruding geometries on the side facing the compressor housing cover. These geometries engage in recesses of the working chamber and thus extend the guide for the piston ring at the critical points of piston ring assembly. This refers to the geometry of the exhaust port on the cylinder bore resulting from the machining or manufacturing of the exhaust port arranged radially to the cylinder bore. The machining process results in the "recess geometry."

[0029] The aforementioned methods for mounting a piston assembly in the working chamber of a radial piston compressor using a mounting device, such as a mounting sleeve, can be implemented with both a piston with a conventional piston ring and a piston with a chamfered piston ring. The mounting sleeve is removed after assembly.

[0030] Further features and advantages of the present invention will become clear from the following description of preferred embodiments with reference to the accompanying figures. These show Fig. 1a a radial piston compressor according to the prior art in a side sectional view; Fig. 1b a radial piston compressor according to the prior art in a cutaway view from the front; Fig. 2a a radial piston compressor according to the prior art in a side sectional view; Fig. 2b a detail of a radial piston compressor, in particular the area of ​​a piston-working chamber combination, in particular a piston with piston ring; Fig. 3 an exploded view of a piston of a radial piston compressor; Fig. 4 a perspective view of a piston of a radial piston compressor with an inserted piston ring; Fig. 5 a perspective view of a workspace without a cylinder head cover; Fig. 6 a perspective view of a workspace without a cylinder head cover; Fig. 7-10 partially cropped perspective views of a working space with pistons without cylinder head covers; Fig. 11 a piston of a radial piston compressor in a cutaway view with a piston ring according to the prior art; Fig. 12 a detail according to Fig. 11; Fig. 13 a piston of a radial piston compressor according to the invention in a cutaway view with a piston ring with chamfer; Fig. 14 a detail according to Fig. 13; Fig. 15 a detail of a radial piston compressor according to the invention with the mounting sleeve according to the invention inserted in a cutaway side view; Fig. 16 a mounting sleeve according to the invention in a perspective view; Fig. 17 an assembly aid according to the invention, inserted into or onto the working space of a radial piston compressor in a cut side view (without piston); Fig. 18 an assembly aid according to the invention, inserted in or onto the working space of a radial piston compressor in a cutaway perspective view (without piston); Fig. 19 a detail of a radial piston compressor according to the invention with the mounting sleeve according to the invention inserted in a cutaway side view; Fig. 20 a piston ring with two chamfers for a radial piston compressor according to the invention in a sectional view.

[0031] The following reference symbols are used in the illustrations: D axis of rotation K Piston axis M Mounting sleeve A Front surface (cylinder head) B milling pocket C milling pocket Z workspace wall (cylinder wall) K edge H height of the piston ring h (greatest) milling pocket depth 1b Negative geometry 1c Negative geometry 1A contact surface 1 compressor unit 2 Drive unit 3 first bearing (drive housing) 4 second bearing (compressor housing cover) 5 third bearing (compressor housing) 11 Drive shaft 12 eccentric discs 13 piston-working chamber combination 14 Piston guide ring 15 Cylinder head, cylinder cover 16 Compressor housing / cylinder housing 17 Compressor housing cover 21 Drive housings 22 Rotor (sheet metal package) 131 Working space / cylinder bore 132 pistons 133 Transmission element 134 piston ring 134' Piston ring with chamfer 1321 Piston ring groove 1341 Phase 1342 (second) phase

[0032] Features and details described in connection with a method naturally also apply to the device according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always makes or can make reciprocal reference. Furthermore, any described method according to the invention can be carried out with the device according to the invention.

[0033] The terminology used herein serves only to describe certain embodiments and is not intended to limit the disclosure. As used herein, the singular forms "a" and "the" are intended to include the plural forms unless the context otherwise makes clear. It will also be clear that the expressions "indicates" and / or "indicating," when used in this description, specify the presence of the aforementioned features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the expression "and / or" includes any and all combinations of one or more of the associated, listed elements.

[0034] First, particular attention will be paid to… Fig. Reference is made to sections 1a to 2b. This refers to a radial piston compressor or piston with piston ring according to the state of the art.

[0035] A radial piston compressor essentially comprises a compressor unit 1 and a drive unit 2. The radial piston compressor includes a housing, which can be composed of individual housing components, such as, for example, in the present embodiment, a drive housing 21, a compressor housing 16, and a compressor housing cover 17. Other housing configurations are also conceivable. The compressor housing 16 can also be referred to as a cylinder housing.

[0036] The compressor unit 1 comprises a drive shaft 11 with an eccentric disc 12. The combination of drive shaft 11 and eccentric disc 12 can also be referred to as an eccentric shaft. The drive shaft 11 has a rotational axis D. The compressor unit comprises at least one piston-working chamber combination 13, preferably several piston-working chamber combinations 13, 13a, 13b... 13f, arranged radially around the drive shaft 11. The piston-working chamber combination 13 can also be described as having a star-shaped arrangement around the drive shaft 11. The piston-working chamber combination 13 comprises a working chamber 131 with a piston 132 slidably arranged therein. The piston 132 has a piston axis K. The direction of displacement of the piston 132 corresponds to the piston axis K. The working chamber 131 can also be referred to as a cylinder bore or cylinder. The working chamber 131 is equipped with a cylinder head 15 at the head end.The cylinder head rests on an end face A. The working chambers 131 of the piston-working chamber combinations 13 can be formed at least partially from the compressor housing 16.

[0037] The drive shaft 11, in turn, can be set in rotation by the drive unit 2, which can, for example, be designed as an electric machine. The drive shaft 11 extends essentially through the drive unit and the compressor unit and is equipped with a rotor 22 on the drive unit 2 side. The rotor 22 is preferably designed as a laminated core. For illustrative purposes, the associated stator of the drive unit, which is designed as an electric machine, is not shown. It is also evident that the rotor 22 is arranged coaxially on the drive shaft 11.

[0038] The rotation of the drive shaft 11 causes the eccentric disk 12 to engage the piston 132 and move it within the working chamber 131, thereby compressing the medium in the working chamber, for example, a refrigerant. The return movement of the piston 132 can be effected, for example, by a piston guide ring 14 in contact with the piston 132. In this way, the piston 132 can be moved back to bottom dead center (BDC) until the eccentric disk 12 again engages the piston crown. The piston 132, particularly the piston crown, can also be equipped with a transmission element 133, or a transmission element 133 can be arranged between the eccentric disk 12 and the piston 132. The transmission element 133 transfers the stroke of the eccentric disk 12 to the piston 132, enabling it to perform the compression movement towards top dead center (TDC).The transmission element 133 can, for example, be made of a different material than the piston 132 and eccentric disc 12, in particular plastic. This can, for example, reduce wear or achieve a certain degree of damping when the eccentric disc 12 impacts. The eccentric disc 12 can also be equipped with an eccentric bearing 121, in particular a needle bearing.

[0039] It is also apparent ( Fig. 2a) that the eccentric shaft is rotatably mounted in the housing by three bearings 3, 4, 5. The individual bearings can be further described with regard to their position within the radial piston compressor. For example, the first bearing 3 can be referred to as the bearing in the drive housing 21. The second bearing 4 is, for example, located in the compressor housing cover 17. The third bearing 5 is located in the compressor housing 16. In principle, the eccentric shaft can also be mounted with only two bearings ( Fig. 1a) be mounted in the housing. Bearings 3, 4, 5 are preferably rolling bearings.

[0040] The further details and operation of a radial piston compressor are sufficiently known to those skilled in the art. For further details, reference can be made, for example, to DE 10 2020 211 680 A1 and DE 10 2022 133 723 A1.

[0041] In the Fig. Figure 2b shows a detail of the radial piston compressor, in particular the area of ​​a piston-working chamber combination 13, in particular a piston 132 of the radial piston compressor.

[0042] It is evident how the piston 132 is received in the working chamber 131. It is provided that the piston 132 is equipped with a circumferential piston ring receptacle 1321 and a piston ring 134 received in the piston ring receptacle.

[0043] The following section will focus in particular on the Fig. 3 and Fig. 4 referenced.

[0044] For mounting the piston 132 into the compressor housing, particularly the working chamber 131, the piston ring 134 (here, in this example, an unslotted PTFE ring) is pre-mounted on the piston 132 itself; that is, the piston ring 134 is already seated in the piston ring groove 1321 of the piston 132. The pre-assembled unit consisting of the piston 132 with the piston ring 134 in the piston ring groove 1321 can be referred to as the "piston assembly." The piston assembly is preferably mounted in the compressor housing, particularly in the working chamber 131, from the outside in. In other words, the piston 132 is inserted into the working chamber 131 in the direction of the eccentric shaft. However, the other mounting direction, from the inside out, is also possible.

[0045] It is evident that the piston ring 134 has a rectangular cross-section. Furthermore, the circumferential, outer edges K of the piston ring 134 are visible, which have a right-angled cross-section.

[0046] The following section will focus in particular on the Fig. 5 and Fig. 6. Referenced.

[0047] In the Fig. 5 and Fig. Figure 6 shows, in particular, surface areas on the compressor housing 16 in the region of the cylinder head 15. The end face A, a first milling pocket B, a second milling pocket C, and a working chamber wall Z with the aforementioned reference numerals are shown. The working chamber wall can also be referred to as the cylinder wall Z. Milling pockets are defined here as, for example, steps, shoulders, or recesses, or the like, which form an edge to or within the cylinder wall.

[0048] Unlike conventional piston assembly in, for example, an internal combustion engine, the end face A, i.e., the "cylinder head" or the surface against which the cylinder head rests, is typically interrupted by "milled pockets" in a radial piston compressor. This means that the edge of the end face A, where it meets the working chamber 131 or the cylinder wall Z, is not continuous and circumferential at a single axial position (relative to the piston axis K), but rather has at least one axial shoulder / offset or step. For the piston ring 134, this means that during assembly, it is at risk of shearing off at the edges of the milled pockets, particularly the first and second milled pockets C, which form at the cylinder wall Z. This problem is exacerbated because, due to functional requirements, the piston ring's outer diameter is usually larger than the piston diameter.

[0049] The following section will focus in particular on the Fig. Reference is made to numbers 7 to 19.

[0050] According to the invention, the piston ring 134' is provided with at least one chamfer 1341 on its outer circumference. In particular, the at least one chamfer 1341 is designed as a chamfer on a circumferential outer edge of the piston ring 134'.

[0051] In other words, a fundamental idea of ​​the invention is to provide a chamfer 1341 on at least one side of the outside of the piston ring 134' so that the piston ring 134' is not damaged at the critical edges when inserted into the working space 131.

[0052] The following section will focus in particular on the Fig. Reference is made to 7 to 10.

[0053] In the Fig. Figures 7 to 10 illustrate, in particular, the assembly of the piston 132 in the associated working chamber 131 in assembly steps. The assembly direction of the piston 132 is preferably from top to bottom.

[0054] In the Fig. In section 7, a critical edge to frontal surface A is identifiable. Fig. 8 shows a critical edge to the milling pocket B. In the Fig. 9 shows a critical edge to the milling pocket C. In the Fig. 10 indicates a preliminary final state.

[0055] During assembly, the piston ring 134' first makes contact at face A, then at milling pocket B, and finally at milling pocket C. This process generally works for face A because the resulting edge can be rounded or chamfered during manufacturing at the work area 131. However, problems arise at milling pockets B and C.

[0056] It is evident that if a piston ring 134', in particular a closed piston ring, is installed on the piston 132, the introduction of the piston assembly 132, 134' into the working chamber 131 would be more difficult, since the piston ring 134' would deflect radially in areas without support and then threaten to shear off at the axial edge, but here a piston ring 134' with a chamfer 1341 is provided which prevents shearing off, or at least makes it less likely.

[0057] The following section will focus in particular on the Fig. Reference is made to pages 11 to 14.

[0058] In the Fig. 12 and Fig. Figure 13 shows, for further clarification, a piston 132 with piston ring 134 according to the prior art in a cross-sectional view, whereas in the Fig. 13 and Fig. Figure 14 shows a piston 132 with piston ring 134' having chamfer 1341 of a radial piston compressor according to the invention. It can be seen that the piston ring is in the Fig. 13 and Fig. 14 is equipped with a chamfer 1341 on an outer edge.

[0059] It is specifically provided that a chamfer 1341 is provided on the piston ring 134' at least on the side facing the joining direction on the outer diameter of the piston ring, so that the piston ring 134' is not damaged on its edges.

[0060] In principle, the proposed piston ring 134' can increase the safety of the piston ring's function and prevent damage to the piston ring 134', since the piston ring 134' can be installed without damage thanks to the chamfer 1341.

[0061] It can be advantageous to provide a circumferential chamfer 1341 and 1342 on both outer edges of the piston ring 134', i.e., the piston ring 134' is equipped with two chamfers 1341 and 1342. This can, in particular, prevent incorrect installation in series production.

[0062] The length and angle of the chamfer 1341 on the piston ring 134' can be adjusted according to requirements.

[0063] The type of edge machining on the piston ring 134', in particular radius, chamfer, etc., can be carried out in different ways.

[0064] The piston ring 134' can be designed as a closed or slotted piston ring, in particular with variation of the slot / joint geometry.

[0065] The height H of the piston ring itself can be variably adjusted, but is usually limited by installation space restrictions.

[0066] For assembly, the higher the piston ring 134' is, the better. The aim should be to make the height H of the piston ring greater than the maximum milling pocket depth h in the cylinder head.

[0067] The following section will focus in particular on the Fig. 15. Reference is made to a piston ring 134' with a large ring height H.

[0068] To clarify relevant heights, the height of the piston ring 134' is marked with the reference symbol H and the greatest milling pocket depth with the reference symbol h.

[0069] The Fig. Figure 15 presents a further possibility for counteracting the risk of piston ring damage during assembly. Here, the ring height H is greater than the maximum milling pocket depth h, measured from the cylinder head surface A. In this case, the piston ring 134' is guided through an assembly sleeve M until it enters the working space 131 below a critical edge.

[0070] According to the invention, a mounting sleeve M can be used for this purpose, which is equipped with at least one negative geometry 1b, 1c.

[0071] This measure can improve piston ring guidance by means of a mounting device, in particular a mounting sleeve M, with a special geometry that forms a counterpart to at least one of the milling pockets, in particular milling pockets B, C, etc., in the working space. Such a mounting sleeve M can also be referred to as a mounting sleeve with "negative geometry".

[0072] The piston assembly 132, 134' can be installed in the working space 131 from both the outside and the inside (from both sides of the cylinder).

[0073] Variations in the manufacturing process of the piston ring 134' are also possible, for example, cutting from a bar with a special tool, injection molding, i.e., chamfer geometry maintained in the injection mold, etc. The manufacturing process is partly dependent on the material of the piston ring 134'.

[0074] The following section will focus in particular on the Fig. Reference is made to pages 16 to 19.

[0075] In the Fig. 16 to Fig. Figure 18 shows a perspective view of an assembly sleeve M according to the invention. The assembly sleeve M is equipped, for example, with a negative geometry 1b corresponding to the milling pocket B and with a negative geometry 1c corresponding to the milling pocket C. Of course, further negative geometries for additional milling pockets can be added. A contact surface 1A of the assembly sleeve M can be used to place the assembly sleeve M against the end face A. Preferably, the negative geometries 1b and 1c engage in the respective milling pockets B and C. The negative geometries 1b and 1c can at least largely cover or reduce the edges of the milling pockets B and C relative to the cylinder wall Z for the piston ring 134, 134' to be mounted, thus guiding the piston ring 134, 134' for a longer period.

[0076] It can therefore be provided that the mounting sleeve M is equipped with at least one negative geometry 1b, 1c. This provides an advantageous aid for facilitating the assembly of the piston assembly 132, 134 into the working chamber 131 of the radial piston compressor. In particular, during the assembly of the piston assembly 132, 134 in the working chamber 131, the piston ring 134 can be guided through the mounting sleeve M until it enters the working chamber 131 below a critical edge of the at least one milled pocket B, C. Advantageously, the negative geometry 1b, 1c can be designed as the inverse geometry of a milled pocket B, C of the cylinder wall Z. In other words, the negative geometry 1b, 1c can, for example, be designed as the inverse geometry of steps, shoulders, recesses, or the like that form an edge to or in the cylinder wall Z.Ultimately, a positive fit is preferably achieved between the milling edge B, C and the negative geometry 1b, 1c.

[0077] The Fig. 19 shows one from Fig. 17 and Fig. Figure 18 shows the attached mounting sleeve M during the joining of the piston assembly 132, 134' with a special embodiment of the mounting sleeve M. The mounting sleeve M has two protruding geometries 1b and 1c on the side facing the compressor housing cover 17, which engage in the recesses of the cylinder housing and thus extend the guide for the piston ring 134' at the critical points of piston ring assembly. The extension of the guide therefore further minimizes the risk of the piston ring 134' being damaged during assembly.

[0078] It is advantageous to use a mounting sleeve M for the secure mounting of the piston assembly 132, 134'.

[0079] Preferably, the clearance between piston 132 and the mounting sleeve M (approx. 10µm) should be as small as possible.

[0080] A high positioning accuracy of the mounting sleeve (mounting device) M to the respective working space 131 should be provided during the assembly process of the piston assembly 132, 134'.

[0081] In Fig. Figure 20 shows a piston ring 134' with a first chamfer 1341 and a second chamfer 1342 in a cutaway view. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 211 680 A1 [0006, 0040] DE 10 2022 133 723 A1 [0006, 0040]

Claims

[1] Radial piston compressor, comprising - a compressor unit (1) and a drive unit (2) for driving the compressor unit, wherein - the compressor unit (1) comprises a plurality of piston-working chamber combinations (13) arranged radially around an eccentric shaft (11, 12) with an axis of rotation (D), wherein - the piston-working chamber combination (13) comprises a working chamber (131) and a piston (132) which can be moved therein, wherein - the piston (132) comprises a piston ring (134) which is received in a circumferential piston ring groove (1321) of the piston, characterized by , that the piston ring (134') is equipped with at least one chamfer (1341) on its outer circumference. [2] Radial piston compressor according to claim 1, characterized by , that at least one chamfer (1341) is designed as a chamfer on a circumferential outer edge of the piston ring (134'). [3] Radial piston compressor according to at least one of the preceding claims, characterized by , that the piston ring (134') is equipped with two chamfers (1341, 1342) which are each provided on the two circumferential outer edges of the piston ring (134'). [4] Radial piston compressor according to at least one of the preceding claims, characterized by , that the piston ring (134') is designed as a closed or slotted piston ring, in particular with variation of the slot / joint geometry. [5] Radial piston compressor according to at least one of the preceding claims, characterized by , that the working space (131) is equipped with at least one milling pocket (B, C), wherein the height (H) of the piston ring (134') is greater than the maximum milling pocket depth (h). [6] Radial piston compressor according to at least one of the preceding claims, characterized by, that the piston ring (134') is designed as a piston ring made of polytetrafluoroethylene (PTFE), in particular as a non-slotted PTFE ring. [7] Mounting sleeve for mounting a piston assembly into the working chamber of a radial piston compressor according to at least one of the preceding claims, wherein the working chamber (131) comprises a cylinder wall (Z), characterized by , that the mounting sleeve (M) is equipped with at least one negative geometry (1b, 1c). [8] Mounting sleeve according to claim 7, characterized by , that the negative geometry (1b, 1c) is designed as the inverse geometry of milling pockets (B, C) of the cylinder wall (Z). [9] Mounting sleeve according to claim 8, characterized by , that the milling pockets (B, C) are designed as steps, ledges, recesses or the like, forming an edge to or in the cylinder wall (Z). [10] Method for assembling a piston assembly comprising a piston (132) with a piston ring (134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims, characterized by , that the piston ring (134') is pre-assembled onto the piston (132) to be inserted into the working chamber (131), wherein the piston (132) with piston ring (134') as a piston assembly is inserted into the working chamber (131). [11] Method according to claim 10, characterized by , that the piston assembly (132, 134') is inserted into the working space (131) from the outside in or from the inside out. [12] Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of claim 1, characterized by, that the working space (131) is equipped with at least one milling pocket (B, C), wherein the milling pocket (B, C) has a milling pocket depth (h) measured from the cylinder head surface (A), wherein the piston ring (134 or 134') has a height (H), wherein the height (H) of the piston ring (134 or 134') is greater than the maximum milling pocket depth (h), wherein the piston ring (134') is guided through a mounting sleeve (M) until it enters the working space (131) below a critical edge of the at least one milling pocket (B, C). [13] Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of claim 1, characterized by, that the working space (131) is equipped with at least one milling pocket (B, C), in particular with more than one milling pocket, wherein a mounting sleeve (M) for inserting the piston assembly (132, 134') is provided, which has at least partially a negative geometry to the arrangement of the milling pockets (B, C) in the working space (131). [14] Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of claim 1, characterized by, that the working space (131) is equipped with at least one milling pocket (B, C), in particular with more than one milling pocket, wherein a mounting sleeve (M) is provided for inserting the piston assembly (132, 134') which has two protruding geometries (1b and 1c) on the side facing the compressor housing (16) which engage in recesses in the cylinder housing and thus extend the guide for the piston ring 134' at the critical points of piston ring assembly.

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