Radial piston compressor and method for the assembly of a radial piston compressor

Abstract

The invention relates to a radial piston compressor, comprising a compressor unit (V) and a drive unit (M) for driving the compressor unit (V), wherein the compressor unit (V) has at least two piston / cylinder bore assemblies (1, 2), preferably a plurality of piston / cylinder bore assemblies (1, 2), which are arranged radially around an eccentric shaft (4), wherein the eccentric shaft (4) is driven by the drive unit (M), wherein each piston / cylinder bore assembly has a piston (1), wherein the radial piston compressor, in particular the compressor unit (V), has a piston-guide ring (13), wherein the pistons (1) are in contact, in particular interlockingly engaged, with the piston-guide ring (13), wherein at least sections, preferably the entirety, of the piston-guide ring (13) are designed to be elastic, in particular elastic in the radial direction. The invention also relates to an advantageous method for the assembly of a radial piston compressor according to the invention.

Description

[0001] Radial piston compressor, and method for assembling a radial piston compressor

[0002] The present invention relates to a radial piston compressor according to the preamble of claim 1, as well as a method for assembling a radial piston compressor according to the preamble of claim 18 or 19.

[0003] A radial piston compressor essentially comprises a compressor unit and a drive device, preferably an electric motor, for driving the compressor unit. The compressor unit essentially comprises a plurality of piston-cylinder bore assemblies arranged radially around an eccentric shaft. The eccentric shaft is driven accordingly by the drive device.

[0004] Furthermore, a radial piston compressor may comprise a piston guide ring which is operatively connected to the pistons of the piston-cylinder bore assemblies in such a way that a return movement can be exerted on the pistons, ie the movement with which the piston is moved from its top dead center to its bottom dead center of the piston movement.

[0005] A radial piston compressor with a piston guide ring is known, for example, from DE 102020211680 A1. In this way, the piston guide ring is generally in contact with the respective piston at one point (without loss of contact), and the piston is brought into contact with the eccentric. This is intended to avoid additional contact changes between the piston guide ring and the piston, as well as between the piston and the eccentric, which has dynamic advantages with regard to the kinematics of the movement sequence and wear-related advantages. Acoustic advantages are also achieved because no rattling noises or other disturbing noises are generated. The piston guide ring keeps the pistons and the transmission elements in sliding contact with the eccentric or with an outer bearing ring of a rolling bearing arranged on the eccentric.

[0006] Also known from DE 103 56 373 A1 is a reciprocating piston machine with radially directed piston-cylinder units arranged next to one another in a ring and with an eccentric shaft extending centrally through a housing body of a machine housing, the eccentric of which shaft controls the outward stroke of the pistons, the inward stroke of the pistons being controlled by a control ring which surrounds the eccentric shaft and its eccentric with a free distance and engages in the pistons, so that the outward stroke of the pistons controls the inward stroke of diametrically oppositely arranged pistons.

[0007] The piston guide ring disclosed in the prior art and designed as a circular ring has little to no flexibility. This flexibility is minimal or non-existent. If the radial distance between the contact points on the piston is not uniform due to manufacturing tolerances of the components, contact gaps arise between the piston guide ring and the piston. Due to this low flexibility, the guide ring cannot compensate for these tolerances or fluctuations in radius or diameter in order to ensure that the pistons constantly rest on the eccentric. For example, the contact gaps are closed at the piston's reversal point from the top dead center position towards the lower positions. This contact closure can, for example, lead to the piston guide ring impacting, which in turn causes negative acoustic effects, i.e. noise.Larger radial distances between the contact points on the piston can, for example, lead to a tighter contact between the piston or swivel segments on the eccentric due to the largely inflexible annulus. The result is, for example, increased friction or wear.

[0008] This is where the present invention comes in and sets itself the task of proposing an improved radial piston compressor, in particular a radial piston compressor that can overcome, or at least reduce, the disadvantages outlined above. In particular, it is an object of the present invention to propose a radial piston compressor with a piston guide ring, whose piston guide ring is designed to constantly form / maintain contact between the piston and the piston guide ring, thus avoiding contact gaps, in order to compensate for tolerances and / or fluctuations in diameter through three contact points of the pistons, in particular to ensure constant contact of the pistons with the eccentric.

[0009] According to the invention, this object is achieved by a radial piston compressor having the characterizing features of claim 1. Because the piston guide ring is designed to be elastic, particularly elastic in the radial direction, at least in sections, the disadvantages outlined above can be overcome or at least reduced.

[0010] A radially elastic guide ring allows for out-of-roundness or a desired deformability in its diameter or effective diameter, so that it comes into and maintains contact with all contact points of the pistons that, due to tolerances, are not on a circular path. All pistons are therefore always in contact with the eccentric. In the area of ​​the piston-guide ring connection, the guide ring is elastic, particularly in the radial direction. This results in constant contact between the pistons and the eccentric. This leads to little to no noise that could arise, for example, from alternating contact and loss of contact between the piston and eccentric. Tolerances or deviations in the effective diameter of the piston guide ring can be compensated for, whereby even "larger" jumps, i.e. out-of-roundness or deviations from the circular shape, are now possible between adjacent pistons.

[0011] Further advantageous embodiments of the proposed invention emerge in particular from the features of the subclaims. The subject matter and features of the various claims can, in principle, be combined with one another in any desired way.

[0012] In an advantageous embodiment of the invention, it can be provided that the elasticity of the piston guide ring is adjusted via its geometry and / or its modulus of elasticity.

[0013] In a further advantageous embodiment of the invention, it can be provided that the piston guide ring has a radial stiffness between 100 N / mm and 1000 N / mm.

[0014] In a further advantageous embodiment of the invention, it can be provided that high-strength and higher-strength steels are suitable as the material for the piston guide ring.

[0015] In a further advantageous embodiment of the invention, the piston guide ring can be provided with an inner circumferential surface. The inner circumferential surface essentially serves to make contact with the pistons, in particular with an active surface of the respective piston. The inner circumferential surface preferably faces the eccentric.

[0016] In a further advantageous embodiment of the invention, it can be provided that the pistons each comprise an active surface for engagement with the piston guide ring. The active surface essentially serves as a contact surface for the piston guide ring.

[0017] In a further advantageous embodiment of the invention, the piston guide ring can comprise a guide ring and spring-elastic elements. Here, it can be provided that the guide ring itself is not elastic, and only the spring-elastic elements are elastic.

[0018] In a further advantageous embodiment of the invention, the spring-elastic elements can extend radially from the inside of the guide ring. This corresponds to the preferred direction of action, so that the spring-elastic elements can be used in a targeted manner.

[0019] In a further advantageous embodiment of the invention, the piston guide ring can be designed to be wider than it is tall. Such a design enables a piston guide ring that is elastic due to its geometry alone. Such a piston guide ring can be manufactured cost-effectively.

[0020] In a further advantageous embodiment of the invention, the dimension of the piston guide ring in the assembled state can be designed to be greater in the axial direction than in the radial direction. Such a design can result in a guide ring that is resilient due to its geometry. Such a piston guide ring can be manufactured accordingly cost-effectively.

[0021] In a further advantageous embodiment of the invention, the piston guide ring can be provided with almost two windings, with the ends of the windings facing each other at a distance from each other on different planes, with the piston guide ring as such having an inner diameter. Such a guide ring is spring-elastic. The profile can be widened to accommodate elasticity.

[0022] In a further advantageous embodiment of the invention, the piston guide ring can be equipped with a means for securing it to one of the pistons. This can counteract circumferential wandering.

[0023] In a further advantageous embodiment of the invention, it can be provided that the piston guide ring consists of a wound material or comprises a wound material.

[0024] In a further advantageous embodiment of the invention, the piston guide ring can be surrounded or at least partially surrounded by a material, in particular a plastic. This allows, for example, further desired properties of the piston guide ring to be adjusted.

[0025] In a further advantageous embodiment of the invention, the piston guide ring can have a V-shaped cross-section. Accordingly, special geometries can be used.

[0026] In a further advantageous embodiment of the invention, the piston guide ring can be designed as a non-closed ring, wherein the piston guide ring has a gap in which the butt ends of the non-closed ring face each other, wherein the piston guide ring has an inner diameter and the butt ends are spaced apart. A piston guide ring designed in this way can be advantageously installed. During installation, the gap can widen and the inner diameter can increase. After installation, the piston guide ring can assume a state with a corresponding preload.

[0027] In a further advantageous embodiment of the invention, the piston guide ring can be designed as a closed ring. In contrast, the piston guide ring can also be designed as a non-closed ring.

[0028] A further object of the present invention is to propose an advantageous method for assembling a piston guide ring in a radial piston compressor according to the invention.

[0029] According to the invention, this object is achieved by the following method steps for a non-closed piston guide ring:

[0030] - the piston guide ring is in a relaxed state, the piston guide ring has a first inner diameter and a first distance between the butt ends;

[0031] - the piston guide ring is transferred to an assembly state, the inner diameter is increased to a second inner diameter, the distance between the butt ends is increased to a second distance;

[0032] - the piston guide ring is applied, in particular with its inner circumferential surface, to the pistons, in particular the second effective surface of the pistons; - the piston guide ring is transferred into an assembled state, the inner diameter is reduced to a third inner diameter, the distance between the butt ends is reduced to a third distance

[0033] - the piston guide ring, in particular the inner circumferential surface, is brought into engagement, in particular positive engagement, with the pistons, in particular with the contact surfaces of the pistons.

[0034] According to the invention, this object is further achieved by the following method steps for a closed piston guide ring:

[0035] - the piston guide ring is in a relaxed state, the piston guide ring has a first inner diameter;

[0036] - the piston guide ring is transferred to an assembly state, the inner diameter is increased to a second inner diameter;

[0037] - the piston guide ring is applied, in particular with its inner circumferential surface, to the pistons, in particular the piston contact surfaces;

[0038] - the piston guide ring is transferred to an assembled state, the inner diameter is reduced to a third inner diameter;

[0039] - the piston guide ring, in particular the inner circumferential surface, is brought into engagement, in particular positive engagement, with the pistons, in particular with the contact surfaces of the pistons.

[0040] Further features and advantages of the present invention will become clear from the following description of preferred embodiments with reference to the accompanying drawings.

[0041] Fig. 1 to 4 details of pistons for piston-cylinder bore assemblies, piston-cylinder bore assemblies for a radial piston compressor and radial piston compressors in various representations according to the prior art;

[0042] Fig. 5 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with an elastic piston guide ring in a first embodiment and a second embodiment;

[0043] Fig. 5a an elastic piston guide ring for a piston-cylinder bore assembly in a perspective view;

[0044] Fig.5b, c a section of an elastic piston guide ring for a radial piston compressor according to the invention in a cross-sectional view;

[0045] Fig. 5d,e an elastic piston guide ring for a radial piston compressor according to the invention in a cross-sectional view;

[0046] Fig. 6 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with an elastic piston guide ring in a third embodiment and a fourth embodiment;

[0047] Fig. 6a shows an elastic piston guide ring for a radial piston compressor according to the invention in a cross-sectional view;

[0048] Fig. 6b shows an elastic piston guide ring for a radial piston compressor according to the invention in a cross-sectional view;

[0049] Fig. 6c-f an elastic piston guide ring for a radial piston compressor according to the invention in a cross-sectional view;

[0050] Fig. 7a shows an elastic piston guide ring for a radial piston compressor according to the invention in a perspective view;

[0051] Fig. 7b shows an elastic piston guide ring for a radial piston compressor according to the invention in a lateral view;

[0052] Fig. 7c shows an elastic piston guide ring for a radial piston compressor according to the invention in a lateral view;

[0053] Fig. 7d shows a side view of an elastic piston guide ring for a radial piston compressor according to the invention; Fig. 8 shows a top view of an elastic piston guide ring for a radial piston compressor according to the invention;

[0054] Fig. 9 shows several pistons of a compressor unit according to the invention with an elastic piston guide ring in a further embodiment;

[0055] Fig. 9a shows an elastic piston guide ring for a radial piston compressor according to the invention in a plan view;

[0056] Fig. 9b shows an elastic piston guide ring for a radial piston compressor according to the invention in a plan view;

[0057] Fig. 9c shows an elastic piston guide ring for a radial piston compressor according to the invention in a plan view;

[0058] Fig. 10 shows an elastic piston guide ring for a radial piston compressor according to the invention in a perspective view;

[0059] Fig. 11 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with elastic piston guide rings in a further embodiment;

[0060] Fig. lla-d sections of elastic piston guide rings in further embodiments.

[0061] The following reference symbols are used in the figures:

[0062] 1 piston

[0063] 2 cylinder bore

[0064] 3 Centerline of the cylinder bore

[0065] 4 Drive shaft / eccentric shaft

[0066] 5 Rotation axis of the drive shaft

[0067] 6 eccentric

[0068] 7 Center of the eccentric

[0069] 8 Transmission element

[0070] 9 first support surface of the transmission element

[0071] 10 cylinder surface

[0072] 11 Effective area of ​​the piston

[0073] 12 second support surface of the transmission element

[0074] 13 Piston guide ring

[0075] 14 Inner surface of the piston guide ring

[0076] 15 Contact surface of the piston

[0077] 16 first support surface radius

[0078] 17 Radius of the cylinder surface 19 Second support surface radius

[0079] 20 second effective area radius

[0080] 21 Center

[0081] 22 first effective area radius

[0082] 23 Radius of the inner surface of the piston guide ring

[0083] 24 Outer surface

[0084] 25 Outer ring

[0085] 26 rolling bearings

[0086] 27 cylinder housing

[0087] 131 Guide ring

[0088] 132 spring-elastic element

[0089] 133 Means for fixing to one of the pistons

[0090] V compressor unit

[0091] M drive device

[0092] A (', ") Gap or distance between the butt ends

[0093] D (', ") inner diameter

[0094] B Width

[0095] H Height

[0096] K plastic cover

[0097] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a" and "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements. Referring first to Figures 1 through 4.

[0098] Here, details of pistons for piston-cylinder bore assemblies, piston-cylinder bore assemblies for a radial piston compressor and according to the state of the art are described in various representations to explain the basic principle.

[0099] A radial piston compressor essentially comprises a compressor unit V and a drive device M for driving the compressor unit V. The compressor unit V essentially comprises a plurality of piston-cylinder bore assemblies 1, 2 arranged radially around an eccentric shaft 4. The eccentric shaft 4 is accordingly driven by the drive device M.

[0100] A piston-cylinder bore assembly essentially comprises a cylinder or cylinder bore 2 and a piston 1 slidably received in the cylinder bore 2.

[0101] The radial piston compressor preferably further comprises a cylinder housing 27 with piston-cylinder bore assemblies accommodated therein. Furthermore, the radial piston compressor comprises the drive shaft 4 with an eccentric 6. The drive shaft 4 is rotated by a drive means 31, preferably an electric motor.

[0102] In contrast to an axial piston compressor, the pistons 1 or cylinders 2 or piston-cylinder bore assemblies 1, 2 extend radially from the drive shaft 4 or eccentric 6. The pistons 1 or cylinders or piston-cylinder bore assemblies are preferably arranged in a star shape around the drive shaft 4 or eccentric 6. The radial piston compressor can also be referred to as a compressor based on the radial piston principle.

[0103] Fig. 1 shows pistons 1 of piston-cylinder bore assemblies in a radial half-section. In Fig. 1, only the axis of rotation 5 of the drive shaft 4 is indicated. Pistons 1 are arranged distributed circumferentially around the drive shaft 4. The center lines 3 of the cylinder bores 2, not shown in Fig. 1 for reasons of better clarity, intersect at the axis of rotation 5 of the drive shaft 4. The cylindrical eccentric 6 is designed as an integral component of the drive shaft 4 or as a component connected in a rotationally fixed manner to the drive shaft 4. The center point 7 of the eccentric 6 is arranged offset by a distance from the axis of rotation 5 of the drive shaft 4 to generate the eccentricity. The eccentric 6 has a cylindrical surface 10 with a radius 17 as its outer surface. The piston-cylinder bore assembly according to the invention further preferably comprises a cylindrical piston guide ring 13, which preferably has an inner outer surface 14.

[0104] A transmission element 8 is preferably arranged between the eccentric 6 and the piston 1 of a piston-cylinder bore assembly. The transmission element 8 transmits the stroke of the eccentric 6 to the piston 1 so that the piston executes the compression movement towards top dead center TDC. In the exemplary embodiment shown in Fig. 1, the transmission elements 8 are supported directly on the cylindrical surface 10 of the eccentric 6 via a first support surface 9. In the exemplary embodiment shown in Fig. 1, the first support surface 9 is designed as a concavely curved cylinder jacket section surface with a first support surface radius 16. The first support surface radius 16 corresponds to the radius 17 of the cylindrical surface 10. The first support surface 9 and the cylindrical surface 10 are thus complementary to one another. In principle, the first support surface 9 could also have a concave shape that deviates from the circular ring shape.

[0105] The transmission element 8 has a convex-shaped second support surface 12. In the exemplary embodiment shown in Fig. 1, the second support surface 12 is designed as a cylinder jacket section surface with a second support surface radius 19. In principle, the second support surface 12 could also have a convex shape deviating from the cylindrical shape instead of a cylinder jacket section shape. The piston 1 is supported on the second support surface 12 of the transmission element 8 via an active surface 11 formed on the piston 1. The active surface 11 of the piston 1 has a concave shape. In the exemplary embodiment shown, the active surface 11 of the piston 1 is designed as a concave cylinder jacket section surface with an active surface radius 22 that corresponds to the second support surface radius 19. The active surface 11 of the piston 1 and the second support surface 12 of the transmission element 8 are thus complementary to one another.In principle, the effective surface 11 of the piston 1 could also have a concave shape deviating from the cylindrical shape.

[0106] A convex-shaped contact surface 15 is formed on the piston 1 or the pistons 1. In the illustrated embodiment, the contact surface 15 of the piston 1 is a cylinder jacket section surface with a contact surface radius 20. The pistons 1 are in engagement with the piston guide ring 13, in particular in a positive-locking engagement with the pistons 13. In particular, via the contact surface 15, the piston is in positive-locking engagement with the piston guide ring 13, in particular with the inner jacket surface 14 of the piston guide ring 13. The engagement, in particular the positive-locking engagement, is effective in the direction of the center line 3 of the cylinder bore 2. The piston guide ring 13 transmits the return movement to the pistons 1, in particular to the contact surface 15 of the pistons 1, i.e. the movement with which the piston 1 is moved from the top dead center TDC to the bottom dead center BDC of the piston movement.

[0107] In the embodiment shown in Fig. 1, the second support surface radius 19 of the transmission element 8 and the second effective surface radius 22 of the piston 1 have the same center point 21. The center point 21 corresponds to the point at which the center line 3 of the cylinder bore 2 pierces the cylindrical surface 10 of the eccentric 6. This design measure preferably ensures that the sum of the radius 17 of the cylindrical surface 10 and the second effective surface radius 22 of the piston 1 corresponds to the radius 23 of the inner circumferential surface 14 of the piston guide ring 13. This ensures that the piston guide ring 13 with its inner circumferential surface 14 generally does not lose contact with the contact surface 15 of the piston 1, i.e. in no angular position of the eccentric 6 or the drive shaft 4. In this way, for example, the piston guide ring 13 is always in contact (without loss of contact) with the respective piston 1.This avoids additional contact changes between the piston guide ring 13 and piston 1, or between the piston 1 and the eccentric 6 or eccentric bearing 25, which offers dynamic advantages with regard to the kinematics of the movement sequence and wear-related advantages. Acoustic advantages are also achieved because no rattling or other disturbing noises are generated.

[0108] As can be seen in Fig. 3, the eccentric 6 can also be equipped with a rolling bearing 26. The rolling bearing 26 generally comprises an outer bearing ring 25, which, instead of the eccentric disc, forms the surface of the eccentric 6 facing the piston 1.

[0109] The piston guide ring 13 guides the pistons 1 on the eccentric 6 (or on the bearing outer ring 25) and prevents the pistons 1 from "lifting off" the cylinder surface 10 (or the outer surface 24 of the outer ring 25 of the rolling bearing) during a downward movement / return movement of the pistons 1. The piston guide ring 13 slides on the second active surface 15 formed on the piston 1. The piston guide ring 13 holds the pistons 1 and the transmission elements 8 in sliding contact with the eccentric 6 (or with a bearing outer ring 25 of a rolling bearing 26 arranged on the eccentric).

[0110] Fig. 2 shows an exploded view of pistons 1 of piston-cylinder bore assemblies. The transmission elements 8 are supported on the outer ring 25 of the rolling bearing 26. The eccentric 6 is not shown in Fig. 2. The contact surface 15 of the piston 1 is also designed to interact with the inner circumferential surface 14 of the piston guide ring 13. Fig. 3 schematically shows a radial piston compressor with piston-cylinder bore assemblies according to the invention. In the illustrated embodiment, the piston-cylinder bore assemblies are designed such that the transmission elements 8 have concave first support surfaces 9 in the shape of a cylinder segment, and the second support surfaces 12 of the transmission elements 8 are designed in the shape of a cylinder segment and interact with the first active surfaces 11 of the pistons 1 in the shape of a cylinder segment.

[0111] The cylinder bores 2 are arranged in a cylinder housing 27. The individual pistons 1 are driven by a single drive shaft 4 with an eccentric 6. For greater clarity, all details typical of a complete radial piston compressor have been omitted from Fig. 3. For example, all valve arrangements and inflow and outflow channels for the refrigerant are missing. Due to the piston-cylinder bore assemblies, the radial piston compressor shown in Fig. 3 is compact in both the radial and axial directions, meaning it requires little installation space in both directions.

[0112] The further relationships and mode of action are well known to those skilled in the art. For further details, reference can be made in particular to DE 10 2020 211 680 A1.

[0113] According to the invention, it is provided that the piston guide ring is designed to be elastic, in particular elastic in the radial direction, at least in sections, preferably completely.

[0114] The elasticity of the piston guide ring can be adjusted via its geometry and / or its modulus of elasticity. Preferably, the piston guide ring has a radial stiffness between 100 N / mm and 1000 N / mm. High-strength and ultra-high-strength steels, for example, are suitable materials for the piston guide ring.

[0115] The piston guide ring 13 has an elasticity in the radial direction, preferably so that it comes into contact with all contact points which, due to tolerances, do not lie on a circular path - ie a desired deformability of the piston guide ring 13 is sought, with the aim of having no contact gap.

[0116] Various embodiments are conceivable for implementing or providing an elastic piston guide ring 13, which will be described below. The embodiments of an elastic piston guide ring presented here are not exhaustive. Further embodiments not shown here are conceivable. Reference is made below to Figs. 5 to 11d.

[0117] Fig. 5 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with two different embodiments of elastic piston guide rings. The piston guide ring 13 shown on the right is shown in perspective in Fig. 5a. The piston guide ring 13 essentially comprises a guide ring 131 and spring-elastic elements 132. The guide ring 131 as such has little elasticity in the radial direction. It can also be seen in Fig. 5 that the spring-elastic elements 132 extend radially from the inside of the guide ring 131.

[0118] Figs. 5b to 5e show further examples of the design of the piston guide ring 13, in particular of the spring-elastic elements 132. The orientation of the spring-elastic elements 132 can be radial, axial, or a mixture of radial and axial orientations, in particular oblique orientations. For example, Fig. 5c shows an oblique orientation of the spring-elastic element 132. Fig. 5b shows a more axial orientation of the spring-elastic element 132.

[0119] In Figs. 5a, 5d and 5e, a diameter D is shown. It is preferably provided that the spring-elastic elements 132 form the diameter D of the piston guide ring 13, which is effective for the pistons 1.

[0120] Fig. 5b and Fig. 5c show a cross-sectional view of the guide rings according to Fig. 5. Reference symbols B denote width, H denote height, and D denote the diameter effective at the piston contact points. The relative position in the assembled state is illustrated by the axis of rotation 5 of the drive shaft. In principle, however, it is also possible for the guide ring 131 and the spring-elastic elements 132 to extend over the entire circumference of the piston guide ring 13, as indicated in Fig. 5d, 5e. Such a piston guide ring 13 is easier to assemble because no precise assignment of the individual spring-elastic elements 132 to the piston contact points is required.

[0121] Fig. 6 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with two different embodiments of elastic piston guide rings 13. The piston guide ring 13 shown on the right is shown in cross-section in part of Fig. 6a. The piston guide ring 13 shown on the left is shown in cross-section in part of Fig. 6b. The piston guide rings 13 shown here are spring-elastic due to their geometry, in particular due to a cross-sectional shape that is wider than it is high. In other words, the extension of the piston guide ring 13 in the assembled state is greater in the axial direction than in the radial direction. The width of the piston guide ring 13 is designated by the reference symbol B and the height by the reference symbol H.

[0122] In Fig. 6c and d, the piston guide rings 13 according to Fig. 6 are shown in a relaxed state. The piston guide rings 13 have an inner diameter D. Fig. 6c and Fig. 6d show the guide rings 13 in cross-section, whereby the rotational axis 5 of the drive shaft 4 is also intended to clarify the position during assembly.

[0123] Fig. 6e shows, by way of example, the piston guide ring 13 according to Fig. 6c in a state during assembly. The piston guide ring 13 has a second inner diameter D'. It can be seen that the second inner diameter D' is larger in a state during assembly than in a relaxed state (D, Fig. 6c). In the aforementioned state, the piston guide ring 13 is threaded on, in particular, over piston contact surfaces 15. This is, in particular, a state in which the piston guide ring 13 should be maximally elastically preloaded.

[0124] Fig. 6f shows the piston guide ring 13 in a mounted state on the piston. The piston guide ring 13 has a third inner diameter D". It can be seen that the third inner diameter D" is smaller in a mounted state than in a state during assembly (D', Fig. 9b). On the other hand, the third diameter D" is larger in a mounted state than in a relaxed state (D, Fig. 9a).

[0125] In the assembled state, the piston guide ring 13 is thus elastically preloaded so that it comes into contact with all contact points (which, due to tolerances, are not located on a circular path), so that no contact gap can form at the contact points of the pistons 1. Preferably, the diameter D of the piston guide ring 13 will always be smaller than the smallest diameter defined by the three contact points of the pistons.

[0126] However, the preload should be as small as possible, since a high preload increases friction, which is undesirable. The preload design must also not exceed the material limits (regarding Hertzian stress and fatigue strength) for both the piston guide ring 13 and the piston contact 15 under continuous load.

[0127] The assembly and the resulting diameters D, D', D" are described and shown here using the example of the piston guide ring 13 with a rectangular cross-section (Figs. 6a, 6c). These explanations also apply to the configurations of the piston guide ring 13 shown in Figures 6b, d and Figures 5, 5a, 5b-5e.

[0128] 7a to 7d only show elastic piston guide rings 13 in various states and views. The piston guide ring 13 shown here has two turns or almost two turns. The turns are arranged one above the other. The butt ends of the turns are spaced apart at a distance A from each other on different planes. The piston guide ring 13 as such has an inner diameter D. The material width of the piston guide ring 13 is designated by reference symbol B. In Figs. 7a and 7b, the piston guide ring 13 is shown in a relaxed state. Accordingly, the aforementioned reference symbols D, A, B refer to the respective sizes in the relaxed state. For better differentiation, reference will be made here to a first inner diameter D and a first distance A.

[0129] In Fig. 7c, the piston guide ring 13 is shown in a maximally elastically preloaded state. The reference numerals used for this purpose are D' and A', respectively. For better differentiation, a second inner diameter D' and a second distance A' are used here. It can be seen that the second distance A' between the butt ends and the second inner diameter D' are larger in a state during assembly than in a relaxed state (A, D, Fig. 7a, 7b).

[0130] In Fig. 7d, the piston guide ring 13 is shown in an elastically preloaded state during operation. The reference numerals used for this purpose are D" and A" accordingly. For better differentiation, a third inner diameter D" and a third distance A" are referred to here. It can be seen that the third distance A" between the butt ends and the third inner diameter D" are smaller in an assembled state than in a state during assembly (A', D', Fig. 7c). On the other hand, the third distance A" and the third diameter D" are larger in an assembled state than in a relaxed state (A, D, Fig. 7a, 7b). Fig. 8 shows an embodiment of an elastic piston guide ring 13 in a plan view. Here, it is provided or recognizable that the piston guide ring 13 is designed as a closed ring.In contrast, some of the embodiments of piston guide rings 13 described below are designed as non-closed rings, i.e. they have an interruption or gap.

[0131] The piston guide ring 13 is equipped with a means 133 for securing it to one of the pistons. Accordingly, no circumferential movement is possible because the piston guide ring is secured to a piston.

[0132] Fig. 9 shows several pistons 1 of a radial piston compressor according to the invention with an elastic piston guide ring 13 in a further embodiment. Figs. 9a to 9c show the piston guide ring 13 from Fig. 9 in various states, which will be discussed below.

[0133] The piston guide ring 13 is a non-closed piston guide ring. In other words, the piston guide ring 13 is not closed; rather, there is a gap where two butt ends of the piston guide ring face each other. The butt ends have a distance A, and the piston guide ring has an inner diameter D, or, as explained later, an inner diameter D' and D" or a distance A' and A". For better differentiation, we will refer here to a first inner diameter D, a second inner diameter D', and a third inner diameter D", as well as a first distance A, a second distance A', and a third distance A".

[0134] In Fig. 9a, the piston guide ring 13 is shown in a relaxed state. The distance between the butt ends is indicated by reference symbol A. The piston guide ring has an inner diameter D.

[0135] Fig. 9b shows the piston guide ring 13 in a state during assembly. The distance between the butt ends is designated by reference symbol A'. The piston guide ring has a second inner diameter D'. It can be seen that the second distance A' between the butt ends and the second inner diameter D' are greater in a state during assembly than in a relaxed state (A, D, Fig. 9a). In the aforementioned state, the piston guide ring 13 is threaded on, in particular, over piston contact surfaces 15. This is, in particular, a state in which the piston guide ring 13 should be maximally elastically preloaded.

[0136] In Fig. 9c, the piston guide ring 13 is shown in a mounted state on the piston. The distance between the butt ends is designated by the reference symbol A". The piston guide ring 13 has a third inner diameter D". It can be seen that the third distance A" between the butt ends and the third inner diameter D" are smaller in a mounted state than in a state during assembly (A', D', Fig. 9b). On the other hand, the third distance A" and the third diameter D" are larger in a mounted state than in a relaxed state (A, D, Fig. 9a). In the mounted state, the piston guide ring is elastically preloaded.

[0137] In summary, two methods for assembling a piston guide ring in a radial piston compressor can be described here, for a non-closed piston guide ring 13 characterized by the following process steps:

[0138] - the piston guide ring 13 is in a relaxed state, the piston guide ring 13 has a first inner diameter D and a first distance A between the butt ends;

[0139] - the piston guide ring 13 is transferred to an assembly state, the inner diameter is increased to a second inner diameter D', the distance between the butt ends is increased to a second distance A';

[0140] - the piston guide ring 13 is applied, in particular with its inner circumferential surface 14, to the pistons 1, in particular the piston contact surfaces 15;

[0141] - the piston guide ring 13 is transferred to an assembled state, the inner diameter is reduced to a third inner diameter D", the distance between the butt ends is reduced to a third distance A";

[0142] - the piston guide ring 13, in particular the inner circumferential surface 14, is brought into engagement, in particular positive engagement, with the pistons 1, in particular with the contact surfaces 15 of the pistons 1.

[0143] Furthermore, for a closed piston guide ring 13: the piston guide ring 13 is in a relaxed state, the piston guide ring 13 has a first inner diameter D; - the piston guide ring 13 is transferred to an assembled state, the inner diameter is increased to a second inner diameter D';

[0144] - the piston guide ring 13 is applied, in particular with its inner circumferential surface 14, to the pistons 1, in particular the piston contact surfaces 15;

[0145] - the piston guide ring 13 is transferred into an assembled state, the inner diameter is reduced to a third inner diameter D";

[0146] - the piston guide ring 13, in particular the inner circumferential surface 14, is brought into engagement, in particular positive engagement, with the pistons 1, in particular with the contact surfaces 15 of the pistons 1.

[0147] Figure 10 shows a perspective view of another embodiment of an elastic piston guide ring 13 for a radial piston compressor according to the invention. This is a closed piston guide ring. The piston guide ring 13 shown here consists of or comprises a coiled material, such as an endless spring.

[0148] Fig. 11 shows a piston-cylinder bore assembly for a radial piston compressor according to the invention with elastic piston guide rings 13 in a further embodiment. The piston guide rings 13 shown schematically here are, in particular, piston guide rings that are surrounded or at least partially surrounded by a material, in particular a plastic. The piston guide ring itself can be designed as a closed or open ring.

[0149] Figs. 11a to 11d show corresponding detailed representations of piston guide rings 13. The piston guide rings 13 of Figs. 11a and 11b represent an elastic piston guide ring made of a wound material, which is at least partially surrounded by a material, in particular plastic K.

[0150] The piston guide rings 13 of Fig. 11c and 11d represent an elastic piston guide ring 13 made of a material with a V-shaped cross-section, which is at least partially surrounded by a material, in particular plastic K.

[0151] It is clear from the exemplary embodiments outlined above that the diameter D, i.e., the effective diameter of the piston guide ring, should always be smaller than the smallest outer diameter defined, for example, by three contact points of the pistons. This means that the ring is then installed with a preload. However, the preload should be as small as possible, since a high preload increases friction, which is undesirable. The design of the preload for the piston guide ring should also not exceed the material limits (particularly with regard to Hertzian stress and fatigue strength) for both the piston guide ring and the piston contact under continuous stress.

[0152] In summary, the following specifications should preferably be considered. The piston guide ring should have the required rigidity so that each piston is in contact with the eccentric with its piston base, and thus the piston stroke curve follows the stroke curve from the eccentric. This results in a particular thermodynamic advantage. The piston guide ring should have the required flexibility, in particular the deformation capacity, to ensure tolerance compensation of the contact points in the radial direction of adjacent pistons. The diameter of the piston guide ring should be oversized to match the diameter of the contact points. Furthermore, the component strength with regard to pressure in contact and fatigue strength under flexural fatigue should be met.

Claims

Claims 1. Radial piston compressor, comprising - a compressor unit (V) and a drive device (M) for driving the compressor unit (V), wherein - the compressor unit (V) comprises at least two piston-cylinder bore assemblies (1, 2), preferably a plurality of piston-cylinder bore assemblies (1, 2), which are arranged radially around an eccentric shaft (4), wherein - the eccentric shaft (4) is driven by the drive device (M), whereby - each piston-cylinder bore assembly comprises a piston (1), wherein - the radial piston compressor, in particular the compressor unit (V), comprises a piston guide ring (13), wherein - the pistons (1) are in contact, in particular in positive engagement, with the piston guide ring (13), characterized in that the piston guide ring (13) is designed to be elastic, in particular elastic in the radial direction, at least in sections, preferably completely.

2. Radial piston compressor according to claim 1, characterized in that the elasticity of the piston guide ring is adjusted via its geometry and / or its modulus of elasticity.

3. Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring has a radial stiffness between 100 N / mm and 1000 N / mm.

4. Radial piston compressor according to at least one of the preceding claims, characterized in that high-strength and higher-strength steels are used as material for the piston guide ring.

5. Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) comprises an inner circumferential surface (14).

6. Radial piston compressor according to at least one of the preceding claims, characterized in that the pistons (1) each comprise a piston contact surface (15) for engagement of the piston guide ring (13). Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) comprises a guide ring (131) and resilient elements (132). Radial piston compressor according to at least one of the preceding claims, characterized in that the resilient elements (132) extend radially, axially, and / or obliquely from the inside of the guide ring (131). Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) is wider (B) than it is high (H). Radial piston compressor according to at least one of the preceding claims, characterized in that the extension of the piston guide ring (13) in the assembled state is greater in the axial direction than in the radial direction.Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) has two turns or almost two turns, the ends of the turns being spaced apart (A, A', A") from one another on different planes, the piston guide ring as such having an inner diameter (D, D', D"). Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) is equipped with a means (133) for fixing to one of the pistons (1). Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) consists of a wound material or comprises a wound material.Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) is surrounded or at least partially surrounded by a material, in particular a plastic (K). Radial piston compressor according to at least one of the preceding claims, characterized in that the piston guide ring (13) has a V-shaped cross-section. Radial piston compressor according to at least one of claims 1 to 15, characterized in that the piston guide ring (13) is designed as a non-closed ring, wherein the piston guide ring has a gap in which abutting ends of the non-closed ring are arranged. closed ring, wherein the piston guide ring has an inner diameter (D, D', D") and the butt ends have a distance (A, A', A"). Radial piston compressor according to at least one of claims 1 to 15, characterized in that the piston guide ring (13) is designed as a closed ring. Method for assembling a piston guide ring in a radial piston compressor according to claim 16, characterized by the following method steps: - the piston guide ring (13) is in a relaxed state, the piston guide ring (13) has a first inner diameter (D) and a first distance (A) between the butt ends; - the piston guide ring (13) is transferred into an assembled state, the inner diameter is increased to a second inner diameter (D'), the distance between the butt ends is increased to a second distance (A'); - the piston guide ring (13) is applied, in particular with its inner circumferential surface (14), to the pistons (1), in particular the piston contact surfaces (15); - the piston guide ring (13) is transferred into an assembled state, the inner diameter is reduced to a third inner diameter (D"), the distance between the butt ends is reduced to a third distance (A”); - the piston guide ring (13), in particular the inner circumferential surface (14), is brought into engagement, in particular positive engagement, with the pistons (1), in particular with the contact surfaces (15) of the pistons (1). A method for assembling a piston guide ring in a radial piston compressor according to claim 17, characterized by the following method steps: - the piston guide ring (13) is in a relaxed state, the piston guide ring (13) has a first inner diameter (D); - the piston guide ring (13) is transferred into an assembled state, the inner diameter is increased to a second inner diameter (D'); - the piston guide ring (13) is applied, in particular with its inner circumferential surface (14), to the pistons (1), in particular the piston contact surfaces (15); - the piston guide ring (13) is transferred into an assembled state, the inner diameter is reduced to a third inner diameter (D"); - the piston guide ring (13), in particular the inner circumferential surface (14), is brought into engagement, in particular positive engagement, with the pistons (1), in particular with the contact surfaces (15) of the pistons (1).

Images