RADIAL PISTON COMPRESSOR

Abstract

A radial piston compressor comprises an eccentric shaft with a rotational axis, comprising an eccentric disk with an eccentric bearing, at least one piston-working chamber combination which extends radially from the eccentric shaft, and a housing, wherein the piston-working chamber combination comprises a working chamber and a piston which is displaceable in the working chamber along a piston axis and which can be driven by the eccentric shaft, wherein a swivel segment is arranged between the eccentric bearing and the piston, wherein the eccentric bearing and the swivel segment are axially fixed at least in portions between a first thrust washer and a second thrust washer, wherein at least one of the thrust washers, preferably both thrust washers, is/are rotationally fixedly connected to the housing.

Description

The present invention concerns a radial piston compressor according to the preamble of claim 1.

A radial piston compressor is an element of fluid technology. In this radial piston compressor, in contrast to an axial piston compressor, at least one piston-working chamber combination is arranged radially and perpendicularly to the drive shaft. A radial piston compressor may also be referred to as a compressor based on the radial piston principle.

The delivery or stroke movement of the piston is usually provoked by an eccentric. In this respect, the drive shaft may also be referred to as an eccentric shaft. As a rule, the radial piston compressor comprises several piston-working chamber combinations which extend in a star shape and radially from the drive shaft or the eccentric shaft.

A piston-working chamber combination essentially comprises a working chamber, also called a cylinder, and a piston which is moved up and down in the working chamber. The piston has a central geometric piston axis which coincides with the displacement direction of the piston. In a radial piston compressor with an eccentric shaft, the piston has a contact face on its side facing the eccentric shaft, which the eccentric disk meets or bears on during rotation of the eccentric shaft. The eccentric shaft has a rotational axis around which the eccentric shaft is rotated. When the eccentric meets the contact face, the piston moves upwards and a medium in the working chamber is compressed.

Radial piston compressors are used, for example, to compress refrigerant in air-conditioning systems of motor vehicles, in particular also in electrically driven vehicles. The medium to be compressed may for example be a refrigerant such as CO2. However, also other media or refrigerants are conceivable.

The following invention relates to the improvement of a refrigerant compressor according to the radial piston principle in the special radial piston compressor, the stroke function of which is transmitted to the pistons by means of a circular eccentric. The implementation of the kinematics, in particular the axial fixing of the eccentric bearing and also the swivel segments, is known for the refrigerant CO2, and usually takes the form of an axial securing means fixed relative to the shaft.

The problem with the above-mentioned axial securing means fixed relative to the shaft is that a high relative speed occurs at the axial sliding contact faces (bearing outer ring/shaft collar or swivel segments/shaft collar) during operation of the piston compressor, and this leads to additional friction losses. In the worst case, with a poor oiling state, increased wear can occur, even leading to the complete failure of the thrust bearing point(s).

Previously known measures to solve/reduce the problem according to the prior art have led to no or to merely inadequate success, such as for example lowering the contact speed by reducing the diameter of the contact to the shaft (speed is dependent on the contact radius in a rotary movement). However, this measure had only a slight effect on lowering the sliding speed.

Also, a reduction in the coefficient of friction between the contact partners, by for example surface coating, particular material pairing, additional oiling and/or particular design of the contact faces (e.g. sequential interruptions for collection of lubricant) were not effective and/or were costly.

The invention described below is intended to solve the problem of the high sliding speeds/relative speeds at the axial contact points of eccentric bearing and swivel segments to the adjacent components.

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 reduced. It is in particular an object of the present invention to propose a radial piston compressor which has lower friction losses and/or less wear.

According to the invention, this object is achieved by a radial piston compressor with the characteristic features of claim 1. Because at least one of the thrust washers, preferably both thrust washers, is/are rotationally fixedly connected to the housing, a radial piston compressor can be proposed which has lower friction losses and/or less wear.

The core concept is to implement the axial fixing of the eccentric bearing and the swivel segments by means of thrust washers which are “fixed relative to the housing”, and thus the relative speed in the contacts of the elements (swivel segments and eccentric bearing outer ring) for axial securing is significantly reduced, to around 1/10th of the relative speeds compared with axial securing elements which are fixed relative to the shaft.

In particular, it is provided that for the special application, in particular the radial piston compressor with eccentric bearing and swivel segments, the axial securing of the above-mentioned elements was previously achieved via the contact “fixed relative to the shaft”, resulting in bearing damage after a short running time.

The solution proposed here enables the axial securing of the swivel segments and the eccentric bearing in the radial piston compressor with very low contact speeds at the axial faces.

Friction losses in the entire system and the risk of wear at the contact points are minimized. This increases the reliability of the entire system for fulfilling the necessary service life requirements.

Furthermore, there is a decoupling of the “shaft” and “piston drive” systems, in particular pistons, swivel segments, eccentric bearing. This allows for larger manufacturing tolerances for the axial dimensions of the shaft and housing. This can result in a cost advantage.

Furthermore, there may be a reduction in the tolerance requirements for a central force application, in particular piston, swivel segment, eccentric bearing. This can result in an advantage in the form of a symmetrical bearing load on the eccentric bearing.

Further advantageous embodiments of the proposed invention arise in particular from the features of the dependent claims. The subjects or features of the various claims may in principle be combined with one another as desired.

In an advantageous embodiment of the invention, it may be provided that at least two, preferably seven, piston-working chamber combinations are arranged in a star shape around the eccentric shaft. Accordingly, there is also a corresponding number of swivel segments arranged between the piston and the eccentric bearing.

In a further advantageous embodiment of the invention, it may be provided that the radial piston compressor forms 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.

In a further advantageous embodiment of the invention, it may be provided that the eccentric shaft comprises an eccentric disk, wherein the width of the eccentric bearing is greater than the width of the eccentric disk. Since the width of the eccentric bearing is greater than the width of the eccentric, the eccentric- and hence also the eccentric bearing-“dips down” radially between the two thrust washers. This guarantees that the axial contact of the components-swivel segments and needle bearing outer ring-covers the entire circumference and the entire surface.

In a further advantageous embodiment of the invention, it may be provided that at least one thrust washer, preferably both thrust washers, is/are fastened to the housing by means of screw connections comprising fastening bores, wherein the fastening bores are arranged coaxially around the rotational axis, wherein the angle between the fastening bores advantageously corresponds to an integral multiple of the number of pistons. This has the advantage that the threaded bores in the cylinder housing can be arranged in a space-saving manner between the piston-working chamber combinations, in particular the pistons.

In a further advantageous embodiment of the invention, it may be provided that a contact face is provided between the at least one thrust washer and the housing, wherein the contact face is oriented plane-parallel to the at least one piston axis or the piston axes. As a result, an exact contact for the thrust washer or washers can be formed.

In a further advantageous embodiment of the invention, it may be provided that the housing comprises a collar at a shoulder in the housing, in particular in the high-pressure region of the radial piston compressor, wherein at least one thrust washer lies against the collar and forms a spring contact on an end face. The spring, in particular when clamped to a component fixed relative to the housing, clamps the thrust washer in a spring-elastic manner. The thrust washer need not be fastened further, i.e. no further fastening element, such as for example a screw connection against the housing, is in principle required for the thrust washer. The elimination of additional fastening elements also results, inter alia, in cost advantages.

In a further advantageous embodiment of the invention, it may be provided that a thrust washer face, in particular in the high-pressure region of the radial piston compressor, is oriented plane-parallel to a contact face between the cylinder housing and the thrust washer on the high-pressure side.

In a further advantageous embodiment of the invention, it may be provided that an eccentric bearing is provided with edge ribs for a needle cage/roller cage. Preferably, an eccentric bearing with edge ribs, in particular on the outer ring of the eccentric bearing, is fitted. The edge ribs fix or guide the needle cage, or limit the axial movability of the needle cage. This has the advantage that, when the needle bearing is axially fixed on the outer ring, in particular via the thrust washers, at the same time the cage of the bearing is also thereby fixed or guided. When a needle bearing without edge ribs is used, the cage of the bearing or the needle bearing ring should be additionally secured, e.g. via the thrust washer, against axial displacement.

In a further advantageous embodiment of the invention, it may be provided that a clearance is provided for the thrust washers. This can advantageously ensure that there is both a clearance for the washers from the shaft and also a sufficiently large axial contact face for guiding the elements.

In a further advantageous embodiment of the invention, it may be provided that at least one of the thrust washers fixed relative to the housing is designed to be removable from the cylinder housing itself. This can in particular ensure an advantageous ease of installation.

In a further advantageous embodiment of the invention, it may be provided that the thrust washers fixed relative to the housing are provided with plane-parallel axial contact faces for the elements to be secured.

In a further advantageous embodiment of the invention, it may be provided that the thrust washers themselves are provided with a plane-parallel contact to the housing. In one embodiment, one of the thrust washers for fixing the eccentric bearing and swivel segment is formed directly in, on or by the housing or on the cylinder housing. Advantageously, an additional component may be omitted. Due to the limited accessibility of the piston, in this design preferably only one piston guide ring is mounted.

In a further advantageous embodiment of the invention, it may be provided that the thrust washers fixed relative to the housing are provided with a fastening, in particular by screws or spring-loaded contact. The above-mentioned measures are distinguished by a capacity for quick installation and in some cases dismantling, in particular for maintenance purposes.

In a further advantageous embodiment of the invention, it may be provided that the thrust washers fixed relative to the housing are provided with an angular orientation relative to the housing. This can in particular achieve the advantage that the contact face for the swivel segments could be designed separately.

Further features and advantages of the present invention will become clear from the following description of preferred exemplary embodiments with reference to the appended drawings. In the drawings:

FIG. 1 shows a perspective, sectional view of a radial piston compressor according to the prior art;

FIG. 1a shows an enlarged detail illustration from FIG. 1;

FIG. 2 shows a schematic illustration to explain the speeds in sliding contacts fixed relative to the shaft;

FIG. 2a shows a schematic illustration to explain the speeds in sliding contacts fixed relative to the shaft;

FIG. 3 shows a schematic illustration to explain the speeds in sliding contacts fixed relative to the shaft;

FIG. 3a shows a schematic illustration to explain the speeds in sliding contacts fixed relative to the shaft;

FIG. 4 shows a radial piston compressor according to the invention in a side sectional view;

FIG. 5 shows a detail of a radial piston compressor according to the invention;

FIG. 6 shows a detail of a radial piston compressor according to the invention;

FIG. 6a shows a detail of a further embodiment of a radial piston compressor according to the invention;

FIG. 7 shows a thrust washer for a radial piston compressor according to the invention, in particular for the low-pressure region, in a perspective view;

FIG. 7a shows a thrust washer for a radial piston compressor according to the invention, in particular for the low-pressure region, in a plan view;

FIG. 7b shows a thrust washer for a radial piston compressor according to the invention, in particular for the low-pressure region, in a side sectional view;

FIG. 8 shows a part of the housing in a perspective view;

FIG. 8a shows a part of the housing in a perspective view;

FIG. 8b shows a detail “Z” from FIG. 8;

FIG. 9 shows a thrust washer for a radial piston compressor according to the invention, in particular for the high-pressure region, in a perspective view;

FIG. 9a shows a thrust washer for a radial piston compressor according to the invention, in particular for the high-pressure region, in a plan view;

FIG. 9b shows a thrust washer for a radial piston compressor according to the invention, in particular for the high-pressure region, in a side sectional view;

FIG. 10 shows a sectional view of a radial piston compressor according to the prior art, with axial contact fixed relative to the shaft;

FIG. 10a is a sectional view of a radial piston compressor according to the invention, with axial contact fixed relative to the housing;

FIG. 11 shows a tolerance chain for a radial piston compressor according to the prior art, with axial contact fixed relative to the shaft;

FIG. 11a shows a tolerance chain for a radial piston compressor according to the invention, with axial contact fixed relative to the housing.

The following reference signs are used in the figures:

• • K Piston axis
  • L Rotational axis
  • H Housing
  • KA Piston-working chamber combination
  • R Working chamber
  • I Eccentric shaft
  • IIa Right thrust washer
  • IIb Left thrust washer
  • III Eccentric bearing
  • IV Swivel segment
  • V Piston
  • VI Mass balancing element
  • VII Right axial contact collar
  • VIII Left axial contact collar
  • HD High-pressure side
  • ND Low-pressure side
  • 1 Cylinder housing
  • 2 Eccentric shaft
  • 3 Piston
  • 4 Piston guide ring
  • 5 Swivel segment
  • 6 Eccentric bearing
  • 7 Thrust washer—low-pressure side
  • 8 Thrust washer—high-pressure side
  • 9 Compressor housing
  • 10 Balancing mass (AGM)—high-pressure side
  • 11 Bearing—high-pressure side
  • 12 Stator housing
  • 13 Bearing—low-pressure side
  • 2a Eccentric (disk)
  • 6a Bearing outer ring
  • 7a Screw for thrust washer—low-pressure side
  • 7b Fastening bore
  • 8a Spring element for thrust washer-high-pressure side
  • S1 Contact swivel segment/thrust washer on the low-pressure side
  • S2 Contact swivel segment/thrust washer on the high-pressure side
  • L1 Contact bearing ring/thrust washer on the low-pressure side
  • L2 Contact bearing ring/thrust washer on the high-pressure side
  • A1 Thrust washer face of the thrust washer on the low-pressure side
  • A2 Thrust washer face of the thrust washer on the high-pressure side
  • G1, G1′ Contact face cylinder housing/thrust washer on the low-pressure side
  • G2, G2′ Contact face cylinder housing/thrust washer on the high-pressure side
  • F1 Contact face bearing on the high-pressure side/spring element
  • F2 Contact face thrust washer on the high-pressure side/spring element

Features and details which are described in connection with a method evidently 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, mutual reference is or can always be made. In addition, any described method according to the invention can be carried out with the device according to the invention.

The terminology used herein serves solely for the purpose of describing particular embodiments and is not intended to limit the disclosure. As used herein, the singular forms “a” and “the” 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 said features, integers, steps, operations, elements and/or components, but do not exclude the presence or the 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.

Firstly, reference is made to FIGS. 1 to 3a.

FIGS. 1 and 1a show a radial piston compressor with an axial securing means “fixed relative to the shaft” for the eccentric bearing and the swivel segments, according to the prior art. A radial piston compressor shown here substantially comprises an eccentric shaft I, a right thrust washer 11a, a left thrust washer IIb, an eccentric bearing III, a swivel segment IV, a piston V, mass balancing element VI, a right axial contact collar VII and a left axial contact collar VIII.

FIG. 1 shows a commonly used strategy for the axial fixing of eccentric bearing III and swivel segments IV. Here, an axial contact collar for the right thrust washer 11a is formed on the eccentric shaft I. This is fixed relative to the shaft and, with its left axial surface VII, forms the axial limitation which limits the displacement “to the right”. The axial displacement of eccentric bearing III and swivel segments IV “to the left” is limited via a thrust washer IIb and its axial contact face VIII, the movement of which relative to the planar surface of the mass balancing element VI is again limited. In this case, the mass balancing element VI is connected to the eccentric shaft I by means of a force fit (via a transverse or longitudinal interference fit). The two thrust washers 11a and 11b are fixed relative to the shaft and therefore rotate at the same speed as the eccentric shaft I.

A detailed description of the problem of sliding speeds is indicated in particular in FIGS. 2, 2a and 3, 3a, to which reference will be made below.

FIG. 2 and FIG. 2a provide an exemplary illustration of the sliding speed between swivel segment IV and thrust washer 11a or IIb (fixed relative to the shaft), in particular a detailed description of the problem of sliding speeds.

A consideration of the movement of the swivel segments IV and their axial faces (contact faces) 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 mean sliding speed in this direction (at a shaft speed of 8000 rpm) is around 2 m/s for a stroke of 8 mm, with a maximum of around 4 m/s. With an axial contact “fixed relative to the shaft”, the contact speed in the shaft rotational direction (at a rotation speed of 8000 rpm and a mean contact radius of 21 mm) is approximately 17.6 m/s.

Reference is now made to FIGS. 3 and 3a. FIGS. 3 and 3a show in particular an illustration of the sliding speed between the eccentric bearing outer ring and the thrust washer (fixed relative to the shaft).

The speed of the eccentric bearing outer ring of the eccentric bearing III in the piston axis direction K is similar to the speed of the swivel segment IV, since these two bodies are always in contact. In the rotational direction (around the eccentric axis I), the bearing outer ring of the eccentric bearing III performs an additional movement (opposite the shaft rotational direction) at around 1/40th of the shaft rotation speed (here around 200 rpm) because of the kinematics of the piston drive. In other words, the end faces of the outer ring of the eccentric bearing III have a maximum relative speed with respect to a contact “fixed relative to the shaft” (for a mean contact diameter of 17.5 mm) of around 15 m/s. (Speed of bearing outer ring+relative speed of washer/housing-relative speed of bearing ring/housing=speed at contact point of bearing outer ring/thrust washer).

The permissible limit value (for sintered materials, around 5 m/s; for special applications with secured oil supply, around 10 m/s) is exceeded at both contacts.

Reference is made below to FIGS. 4 to 11.

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. Preferably, the piston-working chamber combinations KA are 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 which is displaceable in the working chamber along a piston axis K and which can be driven by the eccentric shaft 2. The eccentric shaft 2 has a rotational axis L.

A radial piston compressor according to the invention furthermore comprises in particular a cylinder housing 1, the eccentric shaft 2, the piston or pistons 3, a piston guide ring 4, a swivel segment 5, an eccentric bearing 6, a thrust washer 7 on the low-pressure side ND, screw 7a for thrust washer 7 on the low-pressure side, a thrust washer 8 on the high-pressure side, spring element 8a for the thrust washer on the high-pressure side HD, a compressor housing 9, a balancing mass 10 (abbreviated to 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.

FIG. 4 shows in particular, in longitudinal section, an overview of the assembly of a radial piston compressor with thrust washers 7, 8, fixed relative to the housing, for swivel segments 5 and eccentric bearing 6.

FIG. 4 shows the design of an axial securing means “fixed relative to the housing” for the components swivel segment 5 and eccentric bearing 6. The eccentric shaft 2 is mounted in the low-pressure region ND via the housing bearing 13 in the stator housing 12, in the high-pressure region in the bearing 11 in the compressor housing 9. In the region of the piston axes K, the eccentric 2a or the eccentric disk 2a is formed on the eccentric shaft 2 and transmits the stroke movement to the piston 3 via the eccentric bearing 6 and the swivel 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 simultaneously.

On the low-pressure side ND, a thrust washer 7 is fixed to the cylinder housing 1 by means of fastening elements 7a (in the example, 3× screws M5). This limits the axial position of the swivel segments 5 and the eccentric bearing 6 relative to the cylinder housing 1. On the high-pressure side HD, the thrust washer 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 swivel segments 5 and eccentric bearing 6 towards the HD side.

FIG. 5 shows in particular a detail view of the axial contact points of the swivel segments 5 and the eccentric bearing outer ring 6a.

As can be seen at the top, a housing H of the radial piston compressor may be composed of several housing components, such as for example the cylinder housing 1, the compressor housing 9, and the stator housing 12. Preferably, the thrust washers 7, 8 are fastened to the cylinder housing 1. The cylinder housing preferably forms or contains, at least in portions, the working chambers R of the piston-working chamber combinations KA.

FIG. 5 shows an enlargement of the relevant contact points of the thrust bearing washers 7, 8, fixed relative to the housing, to the components swivel segment 5 and needle bearing outer ring 6.

In particular, the figure shows the contact S1 between swivel segment 5 and thrust washer 7 on the low-pressure side ND, the contact S2 between swivel segment 5 and thrust washer 8 on the high-pressure side HD, the contact L1 between bearing ring 6a and thrust washer 7 on the low-pressure side ND, and the contact L2 between bearing ring 6a and thrust washer 8 on the high-pressure side HD.

As illustrated in FIG. 5, the bearing outer ring 6a of the eccentric bearing 6 is designed as a ring with two edge ribs, the respective inner end faces of which guide the rollers of the needle bearing 6 axially via the bearing cage. The piston 3 is here in the BDC position, i.e. the lowest elevation of the eccentric 2a. The edge ribs preferably fix or guide the needle cage of the needle bearing 6, or limit the axial moveability of the needle cage. This can achieve the advantage that, when the needle bearing is axially fixed, in particular via the thrust bearing washers 7, 8, on the outer ring, the cage of the bearing is also fixed or guided at the same time.

FIG. 6 shows in particular a detail illustration of the contact faces of the thrust washers to the housing.

FIG. 6 is in particular a detail illustration of the contact faces of the thrust washers 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 here be in the TDC position).

In particular, the figure shows a thrust washer face A1 of the thrust washer 7 on the low-pressure side ND, a thrust washer face A2 of the thrust washer 8 on the high-pressure side HD, a contact face G1 of the cylinder housing 1 to the thrust washer 7 on the low-pressure side ND, a contact face G2 of the cylinder housing 1 to the thrust washer 8 on the high-pressure side HD, a contact face F1 of the bearing 11 on the high-pressure side to the spring element 8a, and a contact face F2 of the thrust washer 8 on the high-pressure side to the spring element 8a. The thrust washers 7, 8 rest against the bearing 6.

Since the width of the eccentric bearing 6 is greater than the width of the eccentric 2a, the eccentric 2a and hence also the eccentric bearing 6 “dips down” radially between the two thrust washers. This guarantees that the axial contact of the components-swivel segments 5 and bearing outer ring 6a-covers the entire circumference and the entire surface.

FIG. 6a shows an embodiment of the thrust washer 7, fixed relative to the housing, wherein the thrust washer 7 is formed here by the cylinder housing 1. The thrust washer 8, fixed relative to the housing, is fixed to the cylinder housing 1, as described in the other embodiments.

FIGS. 7 to 7b show an exemplary embodiment of the thrust washer 7 for the low-pressure region ND and its angular pitch of the fastening bores 7b.

FIGS. 7 to 7b illustrate a possible embodiment of the thrust washer 7, fixed relative to the housing, on the ND side. Here, the value of the angle between the fastening bores 7b advantageously corresponds to an integral multiple of the number of pistons (in the example here, a 7-piston refrigerant compressor). In the figure, 3/7×360° or 2/7×360°. This has the advantage that the threaded bores in the cylinder housing 1 can be arranged between the pistons 3 in a space-saving manner.

In addition, FIGS. 7 to 7b show the thrust washer face A1 for the contact of the thrust washer 7 on the eccentric bearing outer ring 6a or the swivel segment 5, and the contact face G1 for the contact of the thrust washer 7 on the cylinder housing 1. In addition, the fastening bores 7b for receiving the screws 7a are also shown.

The contact faces G1 on the thrust washer 7 are advantageously configured plane-parallel (at least 0.15) to the formed thrust washer face A1, in particular for contact on the cylinder housing on the ND side.

Likewise, the corresponding faces (or face, if designed as only one face) G1′ on the cylinder housing 1 lie plane-parallel to the piston axes K in order to form an exact contact for the thrust washer 7 or the contact faces G1.

FIGS. 8 to 8b show in particular an illustration of the contact faces G1′ for the contact of the thrust washer 7 on the cylinder housing 1 on the low-pressure side ND. In addition, the fastening bores 7b′ for receiving the fastening screws 7a are shown.

The contact faces G2′ for the contact of the thrust washer 8 on the cylinder housing 1 on the high-pressure side are also shown.

FIGS. 9 to 9b show in particular an illustration of an exemplary embodiment of the thrust washer 8 on the HD side.

FIG. 9 shows an embodiment of the HD-side thrust washer 8, which lies against a small collar G2′ of a shoulder in the cylinder housing 1 (see in particular FIG. 8a) and forms the spring contact on the end face F2.

The thrust washer face A2, like the ND-side thrust washer 7, is also plane-parallel to the face G2.

FIG. 10 and FIG. 10a show a comparison of possible bearing center offsets, in particular in the axial direction (eccentric bearing center to piston axis center) of the two axial contact variants “fixed relative to the shaft” and “fixed relative to the housing”. For the variant “fixed relative to the shaft”, the closing dimension S is around 1 mm; for the variant “fixed relative to the housing”, it is only around 0.25 mm. The reason for the big difference is the significantly shortened tolerance chain in the variant “fixed relative to the housing” with only 4 input dimensions, compared to the variant “fixed relative to the shaft” with 10 dimensions.

FIG. 10 and FIG. 10a furthermore show in particular an illustration of the possible center offset of the eccentric bearing center to the center of the piston axis for both variants. This can result in a reduction of the moving eccentric masses, since the thrust bearing elements 7, 8 are fixed relative to the housing. With an axial contact “fixed relative to the shaft”, a shaft collar is always necessary on the eccentric, which increases the eccentric masses. In the detail illustrations of FIGS. 10, 10a, it is also evident that the eccentric 2 (of the eccentric shaft) is formed wider in the thrust washer design fixed relative to the shaft, and that an additional collar is formed on the shaft to the right of the eccentric 2a (axial contact of bearing) and also arranged eccentrically to the rotational axis. In particular, a moving eccentric mass is provided. In addition, there is also the mass of the two thrust washers (flanged washers), which (since they are fixed relative to the shaft) also rotate eccentrically.

FIG. 11 and FIG. 11a concern in particular an illustration of the imbalances acting on the eccentric in the comparison between an axial contact which is fixed relative to the shaft and an axial contact which is fixed relative to the housing.

FIG. 11 and FIG. 11a show the comparison of the tolerance chains of the two axial contact variants “fixed relative to the shaft” and “fixed relative to the housing” with regard to the imbalances generated on the eccentric. It can be seen that, due to the lower eccentric masses in the case of the axial contact which is fixed relative to the housing, this is only approximately 80% compared to the axial contact which is fixed relative to the shaft.

FIG. 11 shows a tolerance chain of an embodiment with a thrust washer fixed relative to the shaft, in particular according to FIG. 10, where the following values are taken into account: T1 is the center offset of the piston axes from axis K; T3 is the distance of 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 bearing bore/sealing surface (stator housing); T8 is the width of the ND bearing; T9 is the distance between the ND bearing collar/axial collar of the eccentric bearing (eccentric shaft); T10 is the width of the thrust washer; and T11 is the center of the eccentric bearing. This is represented by ME. For the thrust bearings fixed relative to the shaft, this gives S=−0.34 to 0.67. The tolerance chain comprises 10 dimensions.

A tolerance chain of a thrust washer fixed relative to the housing is shown in FIG. 11a, wherein the following variables are taken into account: T1 is the center offset of piston axis/cylinder axis (from maximum play of piston 3); T2 is the distance of the (sheet metal) contact in the cylinder housing to the cylinder bore centers; T12 is the distance contact/thrust bearing face on the ND axial plate.

T13 indicates half the width of the eccentric bearing outer ring (needle bearing). For the thrust washer 7, 8 fixed relative to the housing according to the invention, this gives S=−0.13 to 0.1. The tolerance chain here comprises 4 dimensions. The axial mounting is here dependent on fewer compressor components or their contact faces and their installation position. It is also evident and understandable that the elimination of the axial contact washers 11a, IIb which are fixed relative to the shaft, the narrower swivel segment 5, the narrower eccentric bearing 6, 6a, the smaller width of the eccentric 2a of the shaft, and the elimination of the axial contact collar on the eccentric shaft, result in a significant reduction in the effective imbalance.

The proposed radial piston compressor can be distinguished in particular by the following features.

Swivel segments 7, 8 and an eccentric bearing 3 with edge ribs for the needle cage/roller cage can be provided.

A clearance for the axial thrust washers 7, 8 on the shaft (left and right of the eccentric 2a) may be provided, in particular to ensure that there is both a clearance for the thrust washers 7, 8 relative to the shaft and a sufficiently large axial contact face for guiding the elements.

The entire system, in particular the shaft with/without rotor, can be assembled/mounted.

At least one of the thrust washers 7 or 8 fixed relative to the housing is designed to be removable from the cylinder housing 1 itself.

Plane-parallel axial contact faces are provided on the thrust washers 7, 8, fixed relative to the housing, for the elements to be secured.

The thrust washers 7, 8 themselves are also arranged in a plane-parallel contact to the housing.

A “fastening” (e.g. screws) of the thrust washers 7, 8 fixed relative to the housing, or a spring-loaded contact is provided.

The proposed radial piston compressor can also be distinguished in particular by the following features.

An angular orientation to the housing 1 of the thrust washers 7, 8 fixed relative to the housing can be provided, with the advantage that the contact face for the swivel segments 5 could be designed separately.

An angular offset between fastening bores 7b on the thrust washer 7 can be provided as an integral multiple of the pitch for the number of pistons, for example 7 pistons: angular offset= 1/7×360° or 2/7×360° (see in particular FIG. 7).

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 lies against the entire axial face of the thrust washer fixed relative to the housing (see in particular FIG. 6a, 6b).

The geometric design of the thrust washers 7, 8, in particular thickness, diameter, etc.; the material pairing, in particular thrust washers/swivel segment, thrust washers/bearing; the additional design of the axial contact face, in particular geometric, technical material coating, etc.; and/or the type of fastening of the thrust washers to the housing, in particular by force fit and form fit, screwed, clamped, spring-loaded, etc., may vary or can be designed by a person skilled in the art.

Claims

1-15. (canceled)

16. A radial piston compressor, comprising:

an eccentric shaft with a rotational axis, including an eccentric disk with an eccentric bearing;

at least one piston-working chamber combination which extends radially from the eccentric shaft; and

a housing;

wherein the piston-working chamber combination includes a working chamber and a piston which is displaceable in the working chamber along a piston axis and which can be driven by the eccentric shaft;

wherein a swivel segment is arranged between the eccentric bearing and the piston;

wherein the eccentric bearing and the swivel segment are axially fixed at least in portions between a first thrust washer and a second thrust washer;

wherein at least one of the thrust washers is rotationally fixedly connected to the housing.

17. The radial piston compressor as claimed in claim 16, wherein both thrust washers are rotationally fixedly connected to the housing.

18. The radial piston compressor as claimed in claim 16, wherein at least two piston-working chamber combinations are arranged in a star shape around the eccentric shaft.

19. The radial piston compressor as claimed in claim 16, wherein seven piston-working chamber combinations are arranged in a star shape around the eccentric shaft.

20. The radial piston compressor as claimed in claim 16, wherein the radial piston compressor forms a low-pressure region and a high-pressure region.

21. The radial piston compressor as claimed in claim 16, wherein the eccentric shaft includes an eccentric disk, wherein the width of the eccentric bearing is greater than the width of the eccentric disk.

22. The radial piston compressor as claimed in claim 16, wherein at least one thrust washer is fastened to the housing by screw connections including fastening bores, wherein the fastening bores are arranged coaxially around the rotational axis, wherein the angle between the fastening bores advantageously corresponds to an integral multiple of the number of pistons.

23. The radial piston compressor as claimed in claim 16, wherein both thrust washers are fastened to the housing by screw connections including fastening bores, wherein the fastening bores are arranged coaxially around the rotational axis, wherein the angle between the fastening bores advantageously corresponds to an integral multiple of the number of pistons.

24. The radial piston compressor as claimed in claim 16, wherein a contact face is provided between the at least one thrust washer and the housing, wherein the contact face is oriented plane-parallel to at least one piston axis or the piston axes.

25. The radial piston compressor as claimed in claim 16, wherein the housing includes a collar at a shoulder in the housing, in particular in the high-pressure region of the radial piston compressor, wherein at least one thrust washer lies against the collar and forms a spring contact on an end face.

26. The radial piston compressor as claimed in claim 16, wherein a thrust washer face, in particular in the high-pressure region of the radial piston compressor, is plane-parallel to a contact face between the housing and the thrust washer on the high-pressure side.

27. The radial piston compressor as claimed in claim 16, wherein an eccentric bearing is provided with edge ribs for a needle cage/roller cage of the eccentric bearing.

28. The radial piston compressor as claimed in claim 16, wherein a clearance is provided for the thrust washers.

29. The radial piston compressor as claimed in claim 16, wherein at least one of the thrust washers fixed relative to the housing is designed to be removable from the housing itself.

30. The radial piston compressor as claimed in claim 16, wherein the thrust washers fixed relative to the housing are provided with plane-parallel axial contact faces for the elements to be secured.

31. The radial piston compressor as claimed in claim 16, wherein the thrust washers themselves are provided with a plane-parallel contact to the housing.

32. The radial piston compressor as claimed in claim 16, wherein the thrust washers fixed relative to the housing are provided with a fastening, in particular by screws or spring-loaded contact.

33. The radial piston compressor as claimed in claim 16, wherein the thrust washers fixed relative to the housing are provided with an angular orientation relative to the housing.