The present invention relates to a radial piston pump, in particular radial piston compressor, according to the preamble of claim 1.
A radial piston pump is an element of fluid technology. In the case of this pump, which can also be regarded as a pump according to the radial piston principle, the piston/working chamber combinations are arranged radially and perpendicular to the drive shaft, in contrast to an axial piston compressor. The delivery or stroke movement of each individual working piston is brought about by an eccentric located on the drive shaft. As a rule, the radial piston pump comprises a plurality of piston/working chamber combinations which extend in a star shape and radially from the drive shaft. The radial piston pump pumps a fluid from a low-pressure chamber into a high-pressure chamber.
Radial piston pumps are used, for example, as compressors for coolant in air conditioning systems of motor vehicles, especially also in electrically driven motor vehicles. A radial piston pump can also be regarded as a radial piston compressor or refrigerant compressor according to the radial piston principle.
In this connection, it is provided that a cover is arranged on the head side of the working chamber or closes same. The cover is accordingly exposed to the pressures prevailing in the working chamber and has to be fixed accordingly.
According to the prior art, the cover is screwed down, for example. It is clear that the outlay on installation is not insignificant if accordingly all of the covers of a radial piston pump with a plurality of piston/working chamber combinations have to be fitted.
In a patent application filed by the applicant, it is proposed to use a common retaining ring to fix all of the covers of the radial piston pump. In order to ensure a distance of the housing component in the radial direction from the retaining ring, the internal diameter of the housing component has to be larger by the distance than the external diameter of the retaining ring. This means that the radial installation space of the entire component is relatively large.
Although an assembly-friendly solution is already proposed here, there is still a need for improvement, especially with regard to the necessary space requirement.
The present invention starts here and makes it the object to propose an improved radial piston pump, in particular to propose a radial piston pump, which is easy to assemble, but also tends to require less space.
According to the invention, this object is achieved by a radial piston pump having the characterizing features of claim 1. Owing to the fact that the radial piston pump is equipped with a housing component with an integrated retaining ring for fixing all of the covers of the radial piston pump, a highly space-saving radial piston pump can be provided. In other words, the function of the retaining ring for fixing the covers is in particular integrated in a separate housing component. The effect achieved by the invention is that only one component takes over the retaining force of the covers and at the same time is part of the housing of the radial piston pump, thus resulting in particular in a reduction in the number of components and/or a simplification of the components. The advantage of this integration is in particular that there is no need to screw down the cover, as a result of which, in particular, working steps can be saved and components for fixing purposes, e.g. screws, securing rings, etc., can be omitted. Furthermore, a reduction in the size of the radial installation space of the entire assembly can be achieved. In particular, the housing screw connection can be placed further inward, i.e. on a smaller hole circle, and thus the external diameter of the entire assembly can be reduced radially. The radial installation space can be reduced with a retaining ring. This results in a smaller pressurized diameter, thereby resulting in a smaller area and thus, in turn, in a lower required axial force. This allows a smaller screw size. Reducing the pressurized internal diameter leads to a reduction in the pressure surface and this then results in a lower axial force. A lower axial force that pushes the housing parts apart means a lower operating force for the housing screw connection. One less of housing screw connection also results from the fact that a smaller diameter means a lower axial force compared to a retaining ring. Advantageously, there is also a lower load on the axial screw connection of the housings, thus associated possibly with a cost reduction by using fewer screws or screws with a lower strength or screws with a smaller diameter. In addition, the pressurized area within the axial sealing faces, especially in the axial direction of the overall component, is smaller. An advantageous secondary effect of the invention is the reduction in the overall screw force; in particular, because of the reduction in the radial installation space, the pressurized area within the housing sealing faces is reduced. A reduced area means a correspondingly reduced force at the same pressure.
Further advantageous refinements of the proposed invention can be found in particular in the features of the dependent claims. The subjects or features of the different claims can in principle be combined with one another as desired.
In an advantageous refinement of the invention, it can be provided that the radial piston pump comprises at least three, preferably eight, piston/working chamber combinations which are arranged in a star shape around the drive shaft. Accordingly, a multiplicity of piston/working chamber combinations can be combined in a compact radial piston pump.
In a further advantageous refinement of the invention, it can be provided that the radial piston pump has at least one further housing component, in particular a high-pressure housing, a cylinder housing, in particular for receiving the piston/working chamber combinations, and/or a stator housing, in particular for receiving a rotor of an electric motor, wherein the housing component with an integrated retaining ring and the further housing component or components form the housing of the radial piston pump. In principle, it is provided that the housing component with an integrated retaining ring and the further housing components form the housing of the radial piston pump. Accordingly, the housing components complement one another to form an overall housing and a correspondingly compact radial piston pump.
In a further advantageous refinement of the invention, it can be provided that the housing component with an integrated retaining ring has plane-parallel axial sealing faces. By means of sealing faces configured in such a way, a tight connection to the adjacent housing component, such as to the cylinder housing, can be provided.
In a further advantageous refinement of the invention, it can be provided that the surfaces of the sealing faces of the housing component with an integrated retaining ring are provided with concentric grooves, in particular with a ripple in the radial direction. The sealing effect can be further improved by the concentric groove or grooves.
In a further advantageous refinement of the invention, it can be provided that contact faces are provided on the housing component with an integrated retaining ring and on the cover, wherein the contact faces are preferably designed such that the housing component with an integrated retaining ring can fix the cover on the cylinder housing.
In a further advantageous refinement of the invention, it can be provided that the contact face with respect to and/or of the respective cover is flat or concave/convex, wherein the curvature of the cover or of the housing component with an integrated retaining ring can preferably run axially with respect to the shaft of the compressor and/or transversely with respect thereto. By such a configuration of the contact faces, an improved mounting of the cover by the housing component with an integrated retaining ring can be ensured.
In a further advantageous refinement of the invention, it can be provided that the cover and/or the housing component with an integrated retaining ring has an overlap in the joint diameter, in particular in the region of the cover on the cylinder housing, such that an interference fit is produced between the cover and the housing-integrated retaining ring. The overlap, also to be referred to as an oversize, can be used for producing or maintaining a press fit by utilizing a certain amount of elasticity from the housing component with an integrated retaining ring. The joint diameter refers to the “common” diameter between the cover and the retaining ring, which, by means of the configuration as an oversize fit, ensures the function of the cover fixing.
In a further advantageous refinement of the invention, it can be provided that one screw is provided for the connection of all of the housing parts. This makes it easy and fast, since all of the housing components can be screwed together or to one another simultaneously.
In a further advantageous refinement of the invention, it can be provided that the housing component with an integrated retaining ring consists of steel or a steel alloy at least in sections. With such a material selection, the high strength requirements of its function as a retaining ring (surface pressure with respect to the cover) can be achieved in an advantageous manner.
In a further advantageous refinement of the invention, it can be provided that surface contact is provided between the cover and the housing component with an integrated retaining ring. An optimum transmission of force and correspondingly little or low punctiform loading can be achieved by surface contact.
In a further advantageous refinement of the invention, it can be provided that the housing component with an integrated retaining ring and the cover at least partially have mutually corresponding shapes. This allows an optimal form fit to be achieved between the housing component with an integrated retaining ring and the cover or the covers. An optimized area means, for example, better distribution of the forces and/or less deformation of the cover.
In a further advantageous refinement of the invention, it can be provided that the housing component with an integrated retaining ring has at least one passage for the housing screw connection, wherein the passage for the housing screw connection is interrupted inwardly or is designed as a fully enclosed passage. While the variant with the interrupted passage is distinguished by less installation space being required, a fully enclosed passage constitutes a good seal against the internal pressure.
In a further advantageous refinement of the invention, it can be provided that at least one, preferably two positioning means, in particular a positioning bore, is/are provided in the housing component with an integrated retaining ring. This makes it possible to ensure that the housing component with an integrated retaining ring is always mounted in a predetermined position. In addition, assembly is facilitated in that the angular position does not have to be determined for each assembly operation.
The radial piston pump proposed here, in particular radial piston compressor, can preferably be used as an air conditioning compressor, preferably with an electric motor as a drive. The fluid is accordingly preferably a refrigerant.
Further features and advantages of the present invention will become apparent from the following description of preferred exemplary embodiments with reference to the accompanying drawings, in which:
The following reference signs are used in the figures:
Here, it goes without saying that features and details which are described in conjunction with a method also apply in conjunction with the apparatus according to the invention, and vice versa, with the result that reference is always made or can always be made mutually to the individual aspects of the invention with regard to the disclosure. Moreover, a possibly described method according to the invention can be carried out by way of the apparatus according to the invention.
The terminology used herein serves only for the purpose of description of particular embodiments, and is not intended to restrict the disclosure. As used herein, the singular forms “a/an” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. In addition, it will become clear that the terms “has” and/or “having”, when used in this description, specify the presence of the stated features, integers, steps, operations, elements and/or components, but do not rule out 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 desired element and all combinations of one or more of the associated, listed elements.
First, reference is made to
A radial piston pump substantially comprises a drive shaft 1 with an eccentric 11, and at least one piston/working chamber combination 2, which is incorporated in a cylinder housing 4. To define the axial direction, a longitudinal axis L of the drive shaft 1 is shown in
As a rule, the radial piston pump comprises at least two piston/working chamber combinations 2, 2a, 2b, . . . which extend radially from the drive shaft 1. Preferably, the radial piston pump comprises at least three, preferably six, piston/working chamber combinations 2, 2a, 2b, . . . which extend correspondingly in a star shape from the drive shaft 1. Accordingly, each piston/working chamber combination 2, 2a, 2b, . . . is provided with a cover 23, 23a, . . . . The piston/working chamber combinations 2, 2a, 2b, . . . are preferably all incorporated in the cylinder housing 4.
Furthermore, a fluid inlet 241 is provided in the cover 23 or on the head side of the working chamber 21. Also, a fluid outlet 251 is provided in the working chamber 21, preferably in the wall of the working chamber 21. The fluid inlet 241 is equipped with an inlet valve 24, which can optionally close or release the fluid inlet 241. The fluid outlet 251 is equipped with an outlet valve 25, which can optionally close or release the fluid outlet 251. Alternatively, it can also be provided that the fluid inlet 241 or the inlet valve 24 is provided in the piston 22, in particular in the piston head. Here, for example, reference can be made to
The fluid F to be compressed flows via the fluid inlet 241 or the inlet valve 24 into the working chamber 21, is compressed there by the stroke movement of the piston 22 and leaves the working chamber 21 through the outlet valve 25 or the fluid outlet 251. Here, for example, reference can be made to
According to the invention, it is provided that the radial piston pump is equipped with a retaining ring 51 integrated in a housing component 5 for all of the covers 23, 23a, . . . of the piston/working chamber combinations 2, 2a, 2b, . . . .
To illustrate the difference over a separate retaining ring, reference should be made to
There are also advantages with regard to the internal diameter of the radial piston pump according to the invention. Accordingly,
The larger internal diameter of the “separate retaining ring” variant in turn causes the axial force to be greater (with the same pressure). A higher axial force means a greater load on the housing screw connection, in particular a higher operating force for the screws. As a measure for maintaining the sealing effect, in particular axially between the housing parts, the preloading force of the screws would have to be increased, a screw material with higher strength would have to be used and/or the number of screws would have to be increased. All of these measures would lead to an increase in costs. Here, the solution according to the invention of the housing component with an integrated retaining ring affords advantages, since here smaller internal surfaces should be expected or be possible and correspondingly lower forces should be expected.
In particular,
Preferably, the housing component 5 with an integrated retaining ring has plane-parallel axial sealing faces 52 in order to be able to ensure the tightness requirements with respect to the adjacent housing parts. Preferably, the surfaces of the sealing faces 52, at least in the region D, are equipped with concentric grooves 521, in particular with a ripple in the radial direction. Preferably, the grooves 521 are configured in the micrometer range, in particular in the sealing region to the outside. Here, in particular, reference can be made to
In a further advantageous refinement of the invention, it can be provided that the housing components 3, 4, 5, 6 for forming the pump housing are screwed together. Preferably, the housing components are jointly screwed together by means of a screw 27. For this purpose, it can be provided that the cylinder housing 4 has a flange 28 or the like, which serves for the screw connection to the further housing components. The cylinder housing may also have a sealing face 52.
Preferably, fluid channels of the radial piston pump, or at least partial regions of fluid channels, can be formed by means of the housing parts which are screwed together. Such an assembled channel is, for example, the high-pressure channel 252.
The housing components 3 to 6 can delimit or seal various pressure regions within the radial piston pump or toward the outside. In a further advantageous refinement of the invention, it can be provided that the housing component has plane-parallel axial sealing faces. By means of sealing faces configured in such a way, a tight connection to the adjacent housing component, such as to the high-pressure housing 7 or to the stator housing 8, can be provided.
Furthermore, it can be provided that seals are arranged in addition to or solely between the sealing faces 52.
In a further advantageous refinement of the invention, it can be provided that the surfaces of the sealing faces 52 have one or more geometric shapes that deviate from a flat or approximately flat face. Thus, it can be provided that, for the targeted formation of contact faces or linear contacts, at least one of the sealing faces 52 has a concave or convex shape. Thus, for example, a flat sealing face 52 of a housing component can be brought into contact with the convex surface or sealing face 52 of another housing component and therefore provide a seal. By means of contact between a flat and a convex surface, a defined linear contact between the two surfaces is advantageously formed. Such a linear contact can preferably entirely or at least partially represent the function of a seal between corresponding components. Advantageously, one of the surfaces can have elastic behavior, and therefore fluctuations in the distance between the components can be compensated by the elasticity.
Preferably, contact faces 53 are provided on the housing component 5 with an integrated retaining ring 51 and contact faces 231 on the cover 23, the contact faces preferably being designed in such a way that the housing component 5 with an integrated retaining ring 51 can fix the cover 23 on the cylinder housing 4, in particular axially and/or radially, thus accordingly against pressure from the working chamber 21.
Further preferably, the cover 23 and the housing component 5 with an integrated retaining ring 51 have an overlap in the joint diameter, in particular in the region of the cover 23 on the cylinder housing 4, such that an interference fit is produced between the cover 23 and the housing-integrated retaining ring 51.
Preferably, a screw is provided for the connection of all of the housing parts; in other words, the housing parts are connected with a single screw, as shown in
It can be advantageous, for example, for the cylinder housing 4 and the housing-integrated retaining ring 5 to form a pre-assembled assembly or a module for assembly. The housing part 5 with the housing-integrated retaining ring 51 fixes all of the covers 23 directly on the cylinder housing 4. The housing parts or the pre-assembled modules can be aligned with one another and then screwed together with at least one screw 27. A further advantage which results from the use of the housing component 5 as a separate component is the ability to pre-assemble (without screws) an assembly comprising the housing component 5 and the cylinder housing 4 (preferably with the cover 23 and the valves 24, 25, piston and optionally seals). This assembly can then be easily screwed to the other housing components and the radial piston pump can be fully assembled. Another advantage is the resulting modularity. The housing components or the housing of the radial piston pump can be produced, for example, by injection molding or diecasting. If a radial piston pump with a different cylinder layout is wanted, e.g. a different cylinder volume or a different arrangement/number of cylinders, the installation space required in the axial direction of the radial piston pump usually also changes. By means of the individually adapted housing component 5, it is possible, for example, to react to a changing axial installation space requirement of a cylinder housing 4 modified in such a way. As long as the contact faces or sealing faces are unchanged, the other housing components can be used without modification. Thus, by means of the housing component 5 with an integrated retaining ring 51, a radial piston pump which is modular and/or scalable in its axial construction length (or performance capability) can be formed. The housing component 5 can also be understood as meaning a housing ring or spacer. Details in this respect are shown in particular in
Preferably, the housing component 5 with an integrated retaining ring 51 should be joined to the cylinder housing 4 with respect to the angular position in an angle-oriented manner so that the passages for the housing screw connection(s) are aligned with one another and the screws can be inserted through or the contact faces 231 or 53 of the cover 23 correspond to the retaining ring 51. For this purpose, it can be provided, for example, that the housing component 5 is 25 equipped with an integrated retaining ring 51 and at least one positioning means, in particular positioning bore. The cylinder housing 4 accordingly has a corresponding positioning means, for example in the form of a pin. The positioning means 54 of the housing component 5 is used in particular for the angular orientation of the integrated retaining ring 51 with respect to the joining device. The cylinder housing should be fixed in the mounting nest in an angle-oriented manner, for example on the clamping slugs or a differently configured geometry. The automated assembly can then join the two housing parts in the correct angular position. The angular orientation is recommended because of the assignment of the contact faces between the cover 23 and integrated retaining ring 51.
By this means, it can be ensured, for example, that, during the assembly, the housing component 5 with an integrated retaining ring 51 can be joined in the correct angular position, for example, for picking up in the gripper of the tool. It can also be advantageously provided that the housing component 5 with an integrated retaining ring 51 is equipped with a second positioning means, in particular second positioning bore 54. A second positioning bore, in particular with an angular offset not equal to 180° with respect to the first positioning bore, is particularly advantageous if, for example, a chamfer or rounding is present on the inner ring edge on one side of the retaining ring 51, which facilitates the joining of the retaining ring 51.
The second positioning bore arranged offset ensures that the housing component 5 with an integrated retaining ring 51 is always installed at the correct angle.
The second positioning bore can be on a different hole circle from the first bore, with the advantage of secure angular alignment, and with the advantage that the housing component 5 then also cannot be installed the wrong way round (rotated 180° about the vertical axis) if a chamfer is provided on one side of it for the joining.
In a further configuration, 3 bores are provided, with one being arranged on a different radius or hole circle. The advantage is, as mentioned above, the clearly angle-oriented and correct side assignment for the housing component.
It can also be preferably provided that the cover 23 has the inlet valve or valves 24.
Preferably, the housing component 5 with an integrated retaining ring 51 should be made of steel or a steel alloy at least in sections, but at least the retaining ring 51 as such, so that it advantageously meets the high strength requirements of its function as a retaining ring (surface pressure with respect to the cover).
The material and/or production method of the housing component 5 with an integrated retaining ring 51 includes all of the materials or production methods known from the prior art, such as casting, turning or milling (coarse and fine).
It may also be preferably provided that the contact face of the cover and/or the associated contact face of the housing component with an integrated retaining ring is flat or concave/convex, wherein the curvature of the cover or the housing component with an integrated retaining ring can run axially with respect to the shaft of the compressor and/or transversely with respect thereto.
It can also be preferably provided that surface contact is provided between the cover and the housing component with an integrated retaining ring.
It can also be preferably provided that compensation of tolerances is provided between the cover and the housing component with an integrated retaining ring.
It can also be preferably provided that the housing component with an integrated retaining ring and the cover at least partially have mutually corresponding shapes.
Possible configurations of the housing component with an integrated retaining ring, in particular the passages thereof for the housing screw connection, are illustrated in particular in
In particular,
Number | Date | Country | Kind |
---|---|---|---|
10 2021 204 716.5 | May 2021 | DE | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2022/061486 | 4/29/2022 | WO |