Radial piston compressor
Patent Information
- Application Number
- EP2024712778
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-17
- Filing Date
- 2024-03-11
- Publication Date
- 2026-01-21
AI Technical Summary
Radial piston compressors experience high friction losses and wear at axial contact points due to high relative speeds in the eccentric bearing and pivoting segments, leading to potential failure, which existing solutions have not adequately addressed.
The axial fixation of eccentric bearing and pivoting segments using rotationally fixed axial bearing washers reduces relative speeds significantly, minimizing friction losses and wear, and decouples the shaft and piston drive systems, allowing for greater manufacturing tolerances and cost advantages.
This solution reduces friction losses and wear, enhancing the system's safety and service life while providing cost benefits and symmetrical bearing loads, and allows for easier assembly and maintenance.
Smart Images
Figure EP2024056334_26092024_PF_FP
Abstract
Description
[0001] Radial piston compressor
[0002] The present invention relates to a radial piston compressor according to the preamble of claim 1.
[0003] A radial piston compressor is a fluid power component. Unlike an axial piston compressor, this type of compressor has at least one piston-working chamber combination 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.
[0004] The piston's displacement or reciprocating motion is usually driven by an eccentric. Therefore, the drive shaft can also be referred to as an eccentric shaft. Radial piston compressors typically comprise several piston-working chamber combinations that extend radially and in a star pattern from the drive shaft or eccentric shaft.
[0005] 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 piston axis that coincides with the piston's direction of travel. In a radial piston compressor with an eccentric shaft, the piston has a contact surface on its side facing the eccentric shaft, against which the eccentric disc impacts or rests during rotation of the eccentric shaft. The eccentric shaft has an axis of rotation about which the eccentric shaft is rotated. When the eccentric impacts the contact surface, the piston moves upwards, compressing a medium in the working chamber.
[0006] Radial piston compressors are used, for example, to compress coolant in motor vehicle air conditioning systems, especially in electrically powered vehicles. A coolant such as CO2 can be used as the compressed medium. However, other media or coolants are also conceivable.
[0007] The following invention relates to the improvement of a refrigerant compressor based on the radial piston principle, in particular a radial piston compressor whose lifting function is transferred to the pistons by means of a circular eccentric. For the refrigerant CO2, the implementation of the kinematics, in particular concerning the axial fixation of the eccentric bearing and the pivoting segments, is known and is generally designed as a shaft-fixed axial locking device. The problem with the above-mentioned shaft-fixed axial locking device is that a high relative speed exists at the axial sliding contact surfaces (bearing outer ring / shaft collar or pivoting segments / shaft collar) during operation of the piston compressor, and this leads to additional friction losses. In the worst case, if the lubrication condition is poor, increased wear can occur and even complete failure of the axial bearing(s).
[0008] Previously known measures to solve or mitigate problems based on the state of the art have been unsuccessful or have only been insufficiently successful. For example, reducing the contact speed by reducing the contact diameter to the shaft (speed depends on the contact radius during rotational movement). However, this measure had only a limited effect on reducing the sliding speed. Reducing the coefficient of friction between the contact partners through, for example, surface coating, special material pairing, additional lubrication, and / or special design of the contact surfaces (e.g., sequential interruptions to collect lubricant) were also ineffective and / or costly.
[0009] The invention described below is designed to solve the problem of high sliding speeds / relative speeds at the axial contact points of eccentric bearings and swivel segments with the adjacent components.
[0010] It is therefore an object of the present invention to propose an improved radial piston compressor, in particular to propose a radial piston compressor with which the problems outlined above can be eliminated or at least mitigated. In particular, the object of the present invention is to propose a radial piston compressor that exhibits lower friction losses and / or less wear.
[0011] According to the invention, this object is achieved by a radial piston compressor having the characterizing features of claim 1. Because at least one of the axial bearing discs, preferably both axial bearing discs, are connected to the housing in a rotationally fixed manner, a radial piston compressor can be proposed which has fewer friction losses and / or less wear.
[0012] The core of the idea is to implement the axial fixation of the eccentric bearing and the swivel segments by means of axial bearing washers, which are arranged "fixed to the housing" and thus significantly reduce the relative speed in the contacts of the axially securing elements (swivel segments and eccentric bearing outer ring) - to approx. 1 / 10 of the relative speeds compared to shaft-fixed axial locking elements.
[0013] It is particularly intended that for the special application, in particular radial piston compressors with eccentric bearings and swivel segments, the axial securing of the above-mentioned elements has always been carried out via the "shaft-fixed" system, with the result that bearing damage occurs after a short running time.
[0014] The solution proposed here enables the axial securing of the swivel segments and the eccentric bearing in the radial piston compressor at very low contact speeds on the axial surfaces.
[0015] Friction losses throughout the entire system, as well as the risk of wear at the contact points, are minimized. This increases the reliability of the entire system to meet the necessary service life requirements.
[0016] Furthermore, the shaft and piston drive systems—especially the pistons, swivel segments, and eccentric bearings—are decoupled. This allows for larger manufacturing tolerances for the axial dimensions of the shaft and housing. This can result in a cost advantage.
[0017] Furthermore, a reduction in tolerance requirements for a central force application, particularly for pistons, swivel segments, and eccentric bearings, may result. This can result in an advantage in the form of symmetrical bearing loading on the eccentric bearing.
[0018] 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.
[0019] In an advantageous embodiment of the invention, at least two, preferably seven, piston-working chamber combinations are arranged in a star shape around the eccentric shaft. This also results in a corresponding number of pivot segments arranged between the piston and the eccentric bearing. In a further advantageous embodiment of the invention, the radial piston compressor can form a low-pressure region and a high-pressure region. The fluid to be compressed, preferably a refrigerant such as CO2, is pumped from the low-pressure region to the high-pressure region.
[0020] In a further advantageous embodiment of the invention, the eccentric shaft can comprise an eccentric disc, with the width of the eccentric bearing being greater than the width of the eccentric disc. Since the width of the eccentric bearing is greater than the width of the eccentric, the eccentric, and thus also the eccentric bearing, "immerses" radially between the two axial bearing discs. This ensures that the axial contact of the components—swivel segments and needle bearing outer ring—is achieved across the entire circumference and surface.
[0021] In a further advantageous embodiment of the invention, at least one axial bearing disc, preferably both axial bearing discs, can be fastened to the housing by means of screw connections comprising fastening holes. The fastening holes are arranged coaxially around the axis of rotation, and the angle between the fastening holes advantageously corresponds to an integer multiple of the number of pistons. This has the advantage that the threaded holes in the cylinder housing can be arranged in a space-saving manner between the piston-working chamber combinations, in particular the pistons.
[0022] In a further advantageous embodiment of the invention, a contact surface can be provided between the at least one axial bearing disk and the housing, wherein the contact surface is aligned plane-parallel to the at least one piston axis(es). This allows for a precise contact for the axial bearing disk(s).
[0023] In a further advantageous embodiment of the invention, the housing can comprise a collar for a shoulder in the housing, particularly in the high-pressure region of the radial piston compressor, with at least one axial bearing disk resting against the collar and forming a spring contact on the end face. The spring, particularly braced by a component fixed to the housing, clamps the axial bearing disk in a spring-elastic manner. The axial bearing disk does not need to be further secured, i.e., in principle, no additional fastening element is required for the axial bearing disk, such as a screw connection to the housing. Eliminating the need for additional fastening elements also results in cost advantages, among other things.
[0024] In a further advantageous embodiment of the invention, it can be provided that an axial bearing disk surface, in particular in the high-pressure region of the radial piston compressor, is aligned plane-parallel to a contact surface between the cylinder housing and the axial bearing disk on the high-pressure side.
[0025] In a further advantageous embodiment of the invention, it can be provided that an eccentric bearing with ribs is provided for a needle roller cage / roller cage. An eccentric bearing with ribs is preferably installed, in particular on the outer ring of the eccentric bearing. The ribs fix or guide the needle roller cage, or limit the axial mobility of the needle roller cage. This has the advantage that when the needle roller bearing is axially fixed to the outer ring, in particular via the axial bearing washers, the bearing cage is also fixed or guided at the same time. When using a needle roller bearing without ribs, the bearing cage or the needle roller bearing race should also be secured against axial displacement, e.g. via the axial bearing washer.
[0026] In a further advantageous embodiment of the invention, a clearance for the axial bearing discs can be provided. This advantageously ensures that there is both clearance for the discs to the shaft and a sufficiently large axial contact surface for guiding the elements.
[0027] In a further advantageous embodiment of the invention, at least one of the axial bearing discs fixed to the housing can be designed to be removable from the cylinder housing itself. This can, in particular, achieve advantageous ease of assembly.
[0028] In a further advantageous embodiment of the invention, it can be provided that plane-parallel axial contact surfaces are provided on the axial bearing discs fixed to the housing to the elements to be secured.
[0029] In a further advantageous embodiment of the invention, it can be provided that the axial bearing discs themselves are arranged in a plane-parallel relationship to the housing. In one embodiment, one of the axial bearing discs is designed to fix the eccentric bearing and pivot segment directly in, on, or through the housing or cylinder housing. Advantageously, an additional component can be omitted. Due to the limited accessibility of the piston, in this embodiment, preferably only a piston guide ring is mounted.
[0030] In a further advantageous embodiment of the invention, the axial bearing discs fixed to the housing can be secured, in particular by screws or a spring-loaded attachment. The aforementioned measures are characterized by quick assembly and, if necessary, disassembly, particularly for maintenance purposes.
[0031] In a further advantageous embodiment of the invention, the axial bearing discs fixed to the housing can be angularly oriented relative to the housing. This provides the particular advantage that the contact surface for the pivoting segments can be designed separately.
[0032] Further features and advantages of the present invention will become clear from the following description of preferred embodiments with reference to the accompanying drawings.
[0033] Fig. 1 is a perspective, sectional view of a radial piston compressor according to the prior art;
[0034] Fig. 1a is an enlarged detail view of Fig. 1;
[0035] Fig. 2 is a schematic diagram to explain the speeds in
[0036] Sliding contacts - shaft-resistant;
[0037] Fig. 2a is a schematic diagram to explain the speeds in sliding contacts - shaft-fixed;
[0038] Fig. 3 is a schematic diagram to explain the speeds in sliding contacts - shaft-fixed;
[0039] Fig. 3a is a schematic diagram to explain the speeds in sliding contacts - shaft-fixed;
[0040] Fig. 4 shows a radial piston compressor according to the invention in a lateral, sectional view;
[0041] Fig. 5 shows a detail of a radial piston compressor according to the invention;
[0042] Fig. 6 shows a detail of a radial piston compressor according to the invention;
[0043] Fig. 6a shows a detail of a further embodiment of a radial piston compressor according to the invention;
[0044] Fig. 7 shows an axial bearing disk for a radial piston compressor according to the invention, in particular for the low-pressure range, in a perspective view;
[0045] Fig. 7a shows an axial bearing disk for a radial piston compressor according to the invention, in particular for the low-pressure range, in a plan view;
[0046] Fig. 7b shows an axial bearing disk for a radial piston compressor according to the invention, in particular for the low-pressure range, in a lateral, sectional view;
[0047] Fig. 8 shows a part of the housing in a perspective view;
[0048] Fig. 8a a part of the housing in a perspective view;
[0049] Fig. 8b a detail «Z» according to Fig. 8;
[0050] Fig. 9 shows an axial bearing disk for a radial piston compressor according to the invention, in particular for the high-pressure range, in a perspective view;
[0051] Fig. 9a shows a top view of an axial bearing disk for a radial piston compressor according to the invention, in particular for the high-pressure range; Fig. 9b shows a side, sectional view of an axial bearing disk for a radial piston compressor according to the invention, in particular for the high-pressure range;
[0052] Fig. 10 is a sectional view of a radial piston compressor according to the prior art - shaft-fixed axial system;
[0053] Fig. 10a is a sectional view of a radial piston compressor according to the invention - axial system fixed to the housing;
[0054] Fig. 11 a tolerance chain for a radial piston compressor according to the state of the art - shaft-fixed axial system;
[0055] Fig. 11a a tolerance chain for a radial piston compressor according to the invention - housing-fixed axial system.
[0056] The following reference symbols are used in the figures:
[0057] K Piston axis
[0058] L axis of rotation
[0059] H Housing
[0060] KA piston-working chamber combination
[0061] R Workspace
[0062] I Eccentric shaft lla Axial bearing disc right llb Axial bearing disc left
[0063] III Eccentric bearing
[0064] IV Swivel segment
[0065] V piston
[0066] VI Mass balancing element
[0067] VII axial contact collar right
[0068] VIII axial contact collar left
[0069] HD high pressure side
[0070] ND low pressure side
[0071] 1 cylinder housing
[0072] 2 eccentric shaft
[0073] 3 Piston 4 Piston guide ring
[0074] 5 swivel segment
[0075] 6 eccentric bearings
[0076] 7 Thrust bearing disc - low pressure side
[0077] 8 Thrust bearing disc - high pressure side
[0078] 9 Compressor housing
[0079] 10 Balancing compound (AGM) - high pressure side
[0080] 11 Bearing - High pressure side
[0081] 12 Stator housing
[0082] 13 Bearings - Low Pressure Side
[0083] 2a Eccentric (disc)
[0084] 6a Bearing outer ring
[0085] 7a Screw for axial bearing disc - low pressure side
[0086] 7b Mounting hole
[0087] 8a Spring element for axial bearing disc - high pressure side
[0088] 51 Contact swivel segment / axial bearing disc on the low pressure side
[0089] 52 Contact swivel segment / axial bearing disc on the high pressure side
[0090] LI Contact bearing ring / axial bearing disc on the low pressure side
[0091] L2 Contact bearing ring / thrust bearing disc on the high pressure side
[0092] Al thrust bearing disc surface of the thrust bearing disc on the low pressure side
[0093] A2 Thrust bearing disc surface of the thrust bearing disc on the high pressure side
[0094] Gl , Gl ' Contact surface cylinder housing / axial bearing disc on the low pressure side
[0095] G2, G2' Contact surface cylinder housing / axial bearing disc on the high pressure side
[0096] Fl contact surface bearing on the high pressure side / spring element
[0097] F2 Contact surface of axial bearing disc on the high pressure side / spring element
[0098] Features and details described in connection with a method naturally also apply in connection with the device according to the invention and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made reciprocally. Furthermore, a method according to the invention that may be described can be carried out with the device according to the invention. The terminology used herein is for the purpose of describing particular embodiments only 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 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.
[0099] First, reference is made to Figs. 1 to 3a.
[0100] Fig. 1 and 1a show a radial piston compressor with a "shaft-fixed axial locking device" for the eccentric bearing and the pivoting segments according to the prior art. The radial piston compressor shown here essentially comprises an eccentric shaft I, a right-hand axial bearing disk IIa, a left-hand axial bearing disk IIb, an eccentric bearing III, a pivoting segment IV, a piston V, a mass balancing element VI, a right-hand axial bearing collar VII, and a left-hand axial bearing collar VIII.
[0101] Fig. 1 shows a commonly used strategy for the axial fixation of eccentric bearing III and swivel segments IV. In this case, an axial contact collar for the right-hand axial bearing disc 11a is designed on the eccentric shaft I. This is shaft-fixed and, with its left axial surface VII, forms the axial limit which restricts displacement “to the right”. The axial displacement of eccentric bearing III and swivel segments IV “to the left” is limited by an axial bearing disc 11b and its axial contact surface VIII, the movement of which is in turn limited relative to the flat surface of the mass balancing element VI. In this case, the mass balancing element VI is connected to the eccentric shaft I by means of a frictional connection (via a transverse or longitudinal interference fit). The two axial bearing discs 11a and 11b are shaft-fixed and therefore rotate at the same speed as the eccentric shaft I.
[0102] A detailed description of the sliding speed problem is provided in particular in Figs. 2, 2a and 3, 3a, respectively, to which reference will be made below. Fig. 2 and Fig. 2a provide an exemplary representation of the sliding speed between swivel segment IV and axial bearing disk IIa and IIb (shaft-fixed), in particular a detailed description of the sliding speed problem.
[0103] An examination of the movement of the swivel segments IV and their axial surfaces (contact surfaces) provides the following insight in particular. The swivel segments IV perform a linear movement in the direction of the piston axis K as their main movement; the speed curve in this direction is sinusoidal. The average sliding speed in this direction (at a shaft speed of 8000 rpm) is around 2 m / s with a stroke of 8 mm, with a maximum of approximately 4 m / s. With a "shaft-fixed" axial contact, the contact speed in the direction of shaft rotation (at a speed of 8000 rpm and an average contact radius of 21 mm) is approximately 17.6 m / s.
[0104] Reference is made below to Figs. 3 and 3a. Figs. 3 and 3a, respectively, show, in particular, a representation of the sliding speed between the eccentric bearing outer ring and the axial bearing disc (shaft-fixed).
[0105] The speed of the eccentric bearing outer ring of eccentric bearing III in the piston axis direction K is analogous to the speed of the swivel segment IV, since these two bodies are always in contact. In the direction of rotation (around the eccentric axis I), the bearing outer ring of eccentric bearing III performs an additional movement (opposite the direction of shaft rotation) at approximately 1 / 40 of the shaft speed (here approximately 200 rpm) due to the kinematics of the piston drive. This means that the end faces of the outer ring of eccentric bearing III have a maximum relative speed with respect to a "shaft-fixed" contact (with an average contact diameter of 17.5 mm) of approximately 15 m / s. (Speed of bearing outer ring + relative speed of disc / housing - relative speed of bearing ring / housing = speed at the contact point between bearing outer ring and axial bearing disc).
[0106] The permissible limit value (for sintered materials approx. 5 m / s; for special applications with secured oil supply approx. 10 m / s) is exceeded at both contacts.
[0107] Reference is made below to Figs. 4 to 11.
[0108] A radial piston compressor according to the invention comprises at least one piston-working chamber combination KA, preferably several piston-working chamber combinations KA, which extend radially from an eccentric shaft 2. The piston-working chamber combinations KA are preferably arranged in a star shape around the eccentric shaft 2. A piston-working chamber combination KA as such comprises a working chamber R and a piston 3 that can be displaced in the working chamber along a piston axis K and can be driven by the eccentric shaft 2. The eccentric shaft 2 has a rotation axis L.
[0109] A radial piston compressor according to the invention further comprises in particular a cylinder housing 1, the eccentric shaft 2, the piston(s) 3, a piston guide ring 4, a pivot segment 5, an eccentric bearing 6, an axial bearing disk 7 on the low-pressure side ND, screw 7a for axial bearing disk 7 on the low-pressure side, an axial bearing disk 8 on the high-pressure side, spring element 8a for axial bearing disk on the high-pressure side HD, a compressor housing 9, a balancing mass 10 (abbreviated AGM) on the high-pressure side, a bearing 11 on the high-pressure side, a stator housing 12, and a bearing 13 on the low-pressure side.
[0110] Fig. 4 shows in particular an overview of the assembly of a radial piston compressor with housing-fixed axial bearing discs 7, 8 for swivel segments 5 and eccentric bearings 6 in longitudinal section.
[0111] Fig. 4 shows the design of a "housing-fixed" axial locking device for the pivot segment 5 and eccentric bearing 6 components. The eccentric shaft 2 is mounted in the stator housing 12 via the housing bearing 13 in the low-pressure area ND and in the compressor housing 9 in its bearing 13 in the high-pressure area. In the area of the piston axes K, the eccentric 2a or eccentric disc 2a is formed on the eccentric shaft 2, which transmits the stroke movement to the piston 3 via the eccentric bearing 6 and the pivot segments 5. The return movement of the pistons 3 takes place via the two piston guide rings 4, which are coupled to all pistons 3 at the same time.
[0112] On the low pressure side ND, an axial bearing disk 7 is fixed to the cylinder housing 1 by means of fastening elements 7a (in the example 3x M5 screws). This limits the axial position of the swivel segments 5 and the eccentric bearing 6 to the cylinder housing 1. On the high pressure side HD, the axial bearing disk 8 is inserted into the cylinder housing 1 from the “left” and fixed to the cylinder housing 1 via the assembly and a spring element 8a and its spring force. The spring force can be supported, for example, on the bearing outer ring of the HD bearing 11. This limits the axial position of the swivel segments 5 and eccentric bearing 6 to the HD side. Fig. 5 shows in particular a detailed view of the axial contact points of the swivel segments 5 and the eccentric bearing outer ring 6a.
[0113] As can be seen above, a housing H of the radial piston compressor can be composed of several housing components, such as the cylinder housing 1, the compressor housing 9, and the stator housing 12. Preferably, the axial bearing discs 7, 8 are attached to the cylinder housing 1. The cylinder housing preferably forms or contains the working chambers R of the piston-working chamber combinations KA, at least in sections.
[0114] Fig. 5 shows an enlargement of the relevant contact points of the housing-fixed axial bearing washers 7, 8 to the components swivel segment 5 and needle bearing outer ring 6.
[0115] In particular, the contact S1 between swivel segment 5 and axial bearing disk 7 on the low pressure side ND, the contact S2 between swivel segment 5 and axial bearing disk 8 on the high pressure side HD, the contact LI between bearing ring 6a and axial bearing disk 7 on the low pressure side ND, and the contact L2 between bearing ring 6 and axial bearing disk 7 on the high pressure side HD are shown.
[0116] As shown in Fig. 5, the bearing outer ring 6a of the eccentric bearing 6 is designed as a ring with two ribs, the respective inner end faces of which axially guide the rollers of the needle bearing 6 via the bearing cage. The piston 3 is located here in the BDC position, i.e., the lowest elevation of the eccentric 6a. The ribs preferably fix or guide the needle cage of the needle bearing 6, or limit the axial mobility of the needle cage. This can achieve the advantage that, with axial fixation, in particular via the axial bearing washers 7, 8, of the needle bearing on the outer ring, the bearing cage is also fixed or guided at the same time.
[0117] Fig. 6 shows in particular a detailed representation of the contact surfaces of the axial bearing discs to the housing.
[0118] Fig. 6 is a detailed representation of the contact surfaces of the axial bearing discs 7, 8 to the housing 1, the eccentric 2a can be seen in the maximum elevation (with an even number of pistons the piston would be in the TDC position here).
[0119] In particular, an axial bearing disk surface Al of the axial bearing disk 7 on the low-pressure side ND, an axial bearing disk surface A2 of the axial bearing disk 8 on the high-pressure side HD, a contact surface Gl from the cylinder housing 1 to the axial bearing disk 7 on the low-pressure side ND, a contact surface G2 from the cylinder housing 1 to the axial bearing disk 8 on the high-pressure side HD, a contact surface Fl from the bearing 6 on the high-pressure side to the spring element 8a, and a contact surface F2 from the axial bearing disk 8 on the high-pressure side to the spring element 8a are shown. The axial bearing disks 7, 8 rest against the bearing 6.
[0120] Since the width of the eccentric bearing 6 is greater than the width of the eccentric 2a, the eccentric 2a and thus also the eccentric bearing 6 "immerse" radially between the two axial bearing discs. This ensures that the axial contact of the components – swivel segments 5 and bearing outer ring 6a – is complete and fully engaged.
[0121] Fig. 6a shows an embodiment of the housing-fixed axial bearing disc 7, wherein the axial bearing disc 7 is formed here by the cylinder housing 1. The housing-fixed axial bearing disc 8 is fixed to the cylinder housing 1, as described in the other embodiments.
[0122] Figs. 7 to 7b show an exemplary design of the axial bearing disc 7 for the low pressure range ND and its angular pitch of the fastening holes 7b.
[0123] Fig. 7 to 7b illustrate a possible embodiment of the housing-mounted axial bearing disk 7 on the low-pressure side. The angle between the mounting holes 7b advantageously corresponds to an integer multiple of the number of pistons (here, in the example, a 7-piston refrigerant compressor). In the figure, 3 / 7x360° or 2 / 7x360°. This has the advantage that the threaded holes in the cylinder housing 1 can be arranged between the pistons 3 in a space-saving manner.
[0124] In addition, Fig. 7 to 7b show the axial bearing disc surface Al for the contact of the axial bearing disc 7 on the eccentric bearing outer ring 6a or the swivel segment 5 as well as the contact surface Gl for the contact of the axial bearing disc 7 on the cylinder housing 1. In addition, the fastening bores 7b for receiving the screws 7a are also shown.
[0125] The contact surfaces Gl on the axial bearing disc 7 should advantageously be plane-parallel (at least 0.15) to the axial bearing disc surface Al, especially for contact with the cylinder housing on the ND side. Likewise, the corresponding surfaces (or surface, if designed as only one surface) Gl 1 on the cylinder housing 1 are plane-parallel to the piston axes K in order to form an exact contact for the axial bearing disc 7 or the contact surfaces Gl.
[0126] Figures 8 to 8b show, in particular, a representation of the contact surfaces G1' for the axial bearing disc 7 to the cylinder housing 1 on the low-pressure side ND. Also shown are the mounting holes 7b' for receiving the mounting screws 7a.
[0127] The contact surfaces G2' for the axial bearing disc 8 on the cylinder housing 1 on the high-pressure side are also shown.
[0128] Fig. 9 to 9b show in particular an illustration of an exemplary embodiment of the HD-side axial bearing disk 8.
[0129] Fig. 9 shows an embodiment of the HD-side axial bearing disc 8, which rests on a small collar G2' to a shoulder in the cylinder housing 1 (see in particular Fig. 8a) and forms the spring system on the end face F2.
[0130] The axial bearing disc surface A2 should also be plane-parallel to the surface G2, analogous to the ND-side axial bearing disc 7.
[0131] Fig. 10 and Fig. 10a show a comparison of possible bearing center offsets, particularly in the axial direction (eccentric bearing center to piston axis center), for the two variants of "shaft-fixed" and "housing-fixed" axial contact. For the shaft-fixed variant, the closed dimension S is approximately 1 mm, while for the housing-fixed variant, it is only approximately 0.25 mm. The reason for this significant difference is the significantly shortened tolerance chain for the housing-fixed variant, with only four dimensions, compared to the shaft-fixed variant with 10 dimensions.
[0132] Fig. 10 and Fig. 10a further show, in particular, an illustration of the possible center offset from the eccentric bearing center to the center of the piston axis for both variants. This can result in a reduction in the moving eccentric masses, since the axial bearing elements 7, 8 are fixed to the housing. With "shaft-fixed" axial contact, a shaft collar is always required on the eccentric, which increases the eccentric masses. The detailed illustrations in Figures 10, 10a also show that the eccentric 2 (of the eccentric shaft) is wider in the shaft-fixed version of the axial bearing disks, and an additional collar is formed on the shaft to the right of the eccentric 2 (axial contact of the bearing) and is also arranged eccentrically to the axis of rotation. In particular, a moving eccentric mass is provided. In addition, there is the mass of the two axial bearing disks (flanges), which (since they are shaft-fixed) also rotate eccentrically.
[0133] Fig. 11 and Fig. 11a relate in particular to a representation of the imbalances acting on the eccentric in comparison between shaft-fixed axial installation and housing-fixed axial installation.
[0134] Figures 11 and 11a compare the tolerance chains of the two variants, "shaft-fixed" and "housing-fixed" axial contact, with respect to the imbalance generated at the eccentric. It can be seen that, due to the lower eccentric masses, the imbalance in the housing-fixed axial contact is only approximately 80% of that in the shaft-fixed axial contact.
[0135] Fig. 11 shows a tolerance chain of a design with a shaft-fixed axial bearing disk, in particular according to Fig. 10, where the following values are taken into account: TI for the center offset of the piston axes to axis K, T3 is the distance from the cylinder bore axis to the sealing flange of the low-pressure seal (cylinder housing), T4 is the width of the low-pressure seal 1; T5 is the width of the housing retaining ring, T6 is the width of the low-pressure seal 2, T7 is the axial stop of the bearing bore / sealing surface (stator housing), T8 is the width of the bearing low-pressure seal, T9 is the distance between the bearing collar low-pressure / axial collar of the eccentric bearing (eccentric shaft), T10 is the width of the axial disk and T11 is the center of the eccentric bearing. This is represented by ME. For the shaft-fixed axial bearing, S = -0.34 to 0.67. The tolerance chain comprises 10 dimensions.
[0136] A tolerance chain of a housing-fixed axial bearing disc is shown in Fig. 11a, taking the following variables into account: TI for the center offset of the piston axis / cylinder axis (from max. clearance of the pistons 3), with T2 the distance of the (sheet metal) contact in the cylinder housing to the cylinder bore centers, with T12 the distance contact / axial bearing surface on the axial plate ND.
[0137] As well as T 13, half the width of the eccentric bearing outer ring (needle bearing). For the housing-fixed axial bearing disk 7, 8 according to the invention, this results in S = -0.13 to 0.1. The tolerance chain here comprises 4 dimensions. The axial bearing here depends on fewer components of the compressor or their contact surfaces and their installation position. It is also evident and understandable that the omission of the shaft-fixed axial contact disks 11a, 11b, the narrower swivel segment 5, the narrower eccentric bearing 6, 6a, the narrower width of the shaft eccentric 2a, and the omission of the axial contact collar on the eccentric shaft result in a significant reduction in the effective imbalance.
[0138] The proposed radial piston compressor can be characterized in particular by the following features.
[0139] Swivel segments 7, 8 and an eccentric bearing 3 with ribs for the needle cage / roller cage can be provided.
[0140] A clearance for the axial thrust bearing discs 7, 8 on the shaft (left and right of the eccentric 6a) can be provided, in particular to ensure that there is both a clearance for the axial thrust bearing discs 7, 8 to the shaft and a sufficiently large axial contact surface for guiding the elements.
[0141] The entire system, especially the shaft with / without rotor, should be able to be joined / assembled.
[0142] At least one of the axial bearing discs 7 or 8 fixed to the housing should be designed to be removable from the cylinder housing 1 itself.
[0143] Plane-parallel axial contact surfaces should be provided on the housing-fixed axial bearing washers 7, 8 to the elements to be secured.
[0144] The axial bearing discs 7, 8 themselves should also be arranged in a plane-parallel relationship to the housing.
[0145] A “fastening” (e.g. screws) of the housing-fixed axial bearing washers 7, 8, or a spring-loaded system should be provided.
[0146] The proposed radial piston compressor can also be characterized in particular by the following features.
[0147] An angular orientation of the housing-fixed axial bearing discs 7, 8 relative to the housing 1 can be provided, with the advantage that the contact surface for the pivoting segments 5 could be designed separately. An angular offset between mounting holes 7b on the axial bearing disc 7 can be provided as an integer multiple of the pitch for the number of pistons, for example, 7 pistons: angular offset = 1 / 7x360° or 2 / 7x360° (see especially Fig. 7).
[0148] It is advantageous if the width of the eccentric bearing 6 is larger than the width of the eccentric 2a on the shaft. This ensures that the bearing outer ring 6a rests against the entire axial surface of the axial bearing disk fixed to the housing (see especially Fig. 6a, 6b).
[0149] The geometric design of the axial bearing discs 7, 8, in particular thickness, diameter, etc., the material pairing, in particular axial bearing discs / swivel segment; axial bearing discs / bearing, the additional design of the axial contact surface, in particular geometric, material-technical coating, etc., and / or the type of fastening of the axial bearing discs to the housing, in particular force-fit; screwed; clamped, spring-loaded, etc., can vary or can be designed by a person skilled in the art.
Claims
Claims 1. Radial piston compressor, comprising - an eccentric shaft (2) with a rotational axis (L), comprising an eccentric disc (2a) with an eccentric bearing (6), - at least one piston-working chamber combination (KA) extending radially from the eccentric shaft (2), - a housing (H), wherein - the piston-working chamber combination (KA) comprises a working chamber (R) and a piston (3) which can be displaced in the working chamber along a piston axis (K) and which can be driven by the eccentric shaft (2), wherein - a pivoting segment (5) is arranged between the eccentric bearing (6) and the piston (3), wherein - the eccentric bearing (6) and the pivoting segment (5) are axially fixed at least in sections between a first axial bearing disc (7) and a second axial bearing disc (8), characterized in that - at least one of the axial bearing discs (7 or 8), preferably both axial bearing discs, are connected to the housing (H) in a rotationally fixed manner.
2. Radial piston compressor according to claim 1, characterized in that at least two, preferably seven, piston-working chamber combinations (KA) are arranged in a star shape around the eccentric shaft (2).
3. Radial piston compressor according to at least one of the preceding claims, characterized in that the radial piston compressor forms a low-pressure region (ND) and a high-pressure region (HD).
4. Radial piston compressor according to at least one of the preceding claims, characterized in that the eccentric shaft (2) comprises an eccentric disc (2a), wherein the width of the eccentric bearing (6) is greater than the width of the eccentric disc (2a).
5. Radial piston compressor according to at least one of the preceding claims, characterized in that at least one axial bearing disc, preferably both axial bearing discs (7, 8), is fastened to the housing (H) by means of screw connections comprising fastening bores (7b), wherein the fastening bores (7b) are coaxially arranged around the rotational axis (L), wherein the angle between the fastening bores (7b) advantageously corresponds to an integer multiple of the number of pistons.
6. Radial piston compressor according to at least one of the preceding claims, characterized in that a contact surface (Gl or G2) is provided between the at least one axial bearing disc (7, 8) and the housing (H), wherein the contact surface (Gl or G2) is aligned plane-parallel to the at least one piston axis (K) or the piston axes.
7. Radial piston compressor according to at least one of the preceding claims, characterized in that the housing (H) comprises a collar (G2) to a shoulder in the housing, in particular in the high-pressure region of the radial piston compressor, wherein at least one axial bearing disc (7 or 8) bears against the collar (G2) and forms a spring system on an end face (F2).
8. Radial piston compressor according to at least one of the preceding claims, characterized in that an axial bearing disc surface (A2), in particular in the high-pressure region of the radial piston compressor, is plane-parallel to a contact surface (G2) between the housing (H) and the axial bearing disc (8) on the high-pressure side.
9. Radial piston compressor according to at least one of the preceding claims, characterized in that an eccentric bearing (6) is equipped with rims for a needle cage / roller cage of the eccentric bearing (6).
10. Radial piston compressor according to at least one of the preceding claims, characterized in that a clearance is provided for the axial bearing discs (7, 8).
11. Radial piston compressor according to at least one of the preceding claims, characterized in that at least one of the axial bearing discs (7, 9) fixed to the housing is designed to be removable from the housing (H) itself.
12. Radial piston compressor according to at least one of the preceding claims, characterized in that plane-parallel axial contact surfaces (Gl, G2) are provided on the axial bearing discs (7, 8) fixed to the housing for the elements to be secured.
13. Radial piston compressor according to at least one of the preceding claims, characterized in that a plane-parallel contact of the axial bearing discs (7, 8) itself to the housing (H) is provided.
14. Radial piston compressor according to at least one of the preceding claims, characterized in that a fastening of the housing-fixed axial bearing discs (7, 8), in particular by screws or spring-loaded system, is provided.
15. Radial piston compressor according to at least one of the preceding claims, characterized in that an angular orientation of the housing-fixed axial bearing discs (7, 8) to the housing (H) is provided.