Radial piston compressor

Abstract

The invention relates to a radial piston compressor comprising a compressor unit (2) and a drive device (1) for driving the compressor unit (2), the compressor unit (2) comprising at least one, preferably a plurality of, piston / working chamber combinations (21, 22) arranged radially about an eccentric shaft (23, 24), each piston / working chamber combination (21, 22) comprising a working chamber (21) with a piston (22), the invention relates to a radial piston compressor, in which a piston (22) is displaceably accommodated, and which is driven by an eccentric shaft (23, 24), the eccentric shaft (23, 24) being rotatably supported in the radial piston compressor by means of at least three bearings, preferably three bearings (3, 4, 5).

Description

[0001] The invention relates to a radial piston compressor according to the preamble of claim 1 .

[0002] A radial piston compressor is a fluid technology component. Unlike axial piston compressors, at least one piston / working chamber combination is arranged radially and perpendicularly to the drive shaft. Radial piston compressors can also be referred to as compressors operating according to the radial piston principle.

[0003] The conveying or lifting motion of the piston is often achieved via an eccentric mechanism. In this case, the drive shaft can also be referred to as the eccentric shaft. Generally speaking, radial piston compressors consist of multiple piston / working chamber combinations that extend radially outward from the drive shaft or eccentric shaft in a star-shaped pattern.

[0004] The piston / working chamber combination essentially consists of a working chamber, also called a cylinder, and a piston that moves up and down within it. The piston has a central, geometric piston axis, which corresponds to the direction of its displacement. In radial piston compressors with an eccentric shaft, the piston has a contact surface on the side facing the eccentric shaft. During the shaft's rotation, the eccentric disc strikes or abuts this contact surface. When the eccentric disc strikes the contact surface, the piston moves upward, compressing the medium in the working chamber.

[0005] Radial piston compressors can be used, for example, to compress refrigerants in air-conditioning systems of motor vehicles, in particular electric vehicles. The medium to be compressed can be a refrigerant such as carbon dioxide (CO2), but can also be other media or refrigerants.

[0006] During the rotation, the refrigerant is drawn in, compressed, and discharged again. This cyclic process has a uniform phase difference between the cylinders corresponding to the number of cylinders.

[0007] The pressure regulated within the cylinder acts on the eccentric pin via the piston surface, thereby exciting the eccentric shaft. The forces generated by all cylinders involved in the compression process are superimposed, ultimately creating a net force on the eccentric shaft. The eccentric shaft, along with its bearings and surrounding housing, forms a vibrating system. This system experiences bending vibrations due to the periodic compression pressure.

[0008] In this system, bending vibrations have a particularly negative impact on the acoustic performance because in the resonance region, the static force balance no longer holds. Resonance occurs when the natural frequency of the vibrating system is equal to the excitation frequency.

[0009] The present invention is based on this and has the object of providing an improved radial piston compressor, in particular a radial piston compressor with improved acoustic properties.

[0010] According to the present invention, this object is achieved by a radial piston compressor having the features of claim 1, characterized in that the eccentric shaft is rotatably supported in the radial piston compressor via at least three bearings, preferably three bearings. In other words, to improve the acoustic performance of the radial piston compressor, resonance intensities can be effectively suppressed by selectively selecting the number of bearings, bearing positions, and / or bearing stiffnesses.

[0011] Further preferred embodiments of the invention emerge in particular from the features of the dependent claims. The subject matter or features of the individual claims can in principle be freely combined with one another.

[0012] In a preferred embodiment of the present invention, the radial piston compressor may include a drive housing, a compressor housing, and a compressor housing cover. In principle, the housing of the radial piston compressor may also include other components or be constructed in a single two-part structure. However, the arrangement of the bearings in the three-part structure shown in this embodiment is advantageous for the preferred embodiment of the present invention, particularly because they are easily accessible in each housing part and facilitate assembly or disassembly, for example, during maintenance.

[0013] In another preferred embodiment of the present invention, the first bearing can be arranged in the compressor housing cover, the second bearing in the compressor housing, and the third bearing in the drive housing. In this case, a preferred arrangement of the bearings relative to the existing housing components is achieved. As described above, the bearings can be easily assembled or disassembled in their respective housing components.

[0014] In another preferred embodiment of the present invention, the first and second bearings can be arranged in the compressor housing, while the third bearing is arranged in the drive housing. In this case, a preferred arrangement of the bearings relative to the existing housing components is achieved. As described above, these bearings can be easily assembled or disassembled in their respective housing components.

[0015] In another preferred embodiment of the present invention, the shaft can form a vibration node through the three bearing positions and their specific arrangement, and the position of the vibration node in the axial direction is close to the load input point.

[0016] In another preferred embodiment of the present invention, the bearing can be a sliding bearing or a rolling bearing, in particular a cylindrical roller bearing or a ball bearing. Such bearing types have excellent bearing rigidity.

[0017] In another preferred embodiment of the present invention, it can be provided that one of the bearings is configured as an axial bearing. Thus, the axial positioning of the eccentric shaft can be achieved through the axial bearing.

[0018] In another preferred embodiment of the present invention, the bearing can be mounted in the housing by press-fitting, which can be easily applied to industrial mass production.

[0019] In another preferred embodiment of the present invention, the eccentric shaft can be axially guided by a fixing ring. The advantage of this design is that the bearing does not need to bear any axial force.

[0020] Other features and advantages of the present invention will become more apparent from the following description of preferred embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 : shows the first bending vibration mode of the shaft with external double-point support;

[0022] Figure 2 : shows the first bending vibration mode of a shaft with three-point support and a vibration node near the excitation position;

[0023] Figure 3 : shows a sectional side view of an eccentric shaft in a radial piston compressor according to the present invention;

[0024] Figure 4 : shows a sectional side view of an embodiment of a radial piston compressor according to the present invention;

[0025] Figure 5 : shows a cross-sectional side view of a radial piston compressor according to another embodiment of the present invention;

[0026] Figure 6 : shows a sectional side view of a radial piston compressor according to yet another embodiment of the present invention;

[0027] Figure 7 : shows a cross-sectional plan view of a radial piston compressor according to the present invention.

[0028] The following reference numerals are used in the drawings:

[0029] S vibration node

[0030] O Excitation and load introduction position

[0031] G Vibration form

[0032] D Rotation axis

[0033] 1. Drive unit

[0034] 2 compressor units

[0035] 3. First bearing

[0036] 4 Second bearing

[0037] 5. Third bearing

[0038] 11 Drive housing

[0039] 12 rotors

[0040] 21 working chamber

[0041] 22 piston

[0042] 23 drive shaft

[0043] 24 eccentric disc

[0044] 25 Compressor housing, cylinder housing

[0045] 26 Compressor housing cover

[0046] 27 Eccentric bearing

[0047] 28 Transfer elements

[0048] 29 Piston guide ring

[0049] 30 fixing ring

[0050] 231 Part 1

[0051] 232 Part 2

[0052] In this case, features and details related to the method according to the invention are of course also applicable to the device according to the invention, and vice versa. Therefore, with respect to the disclosure, references can always be made to the various aspects of the invention. Furthermore, where applicable, the method according to the invention can be implemented by means of the device according to the invention.

[0053] The terms used in this specification are only used to describe the purpose of specific embodiments and should not be regarded as limiting the disclosure of the present invention. The singular forms "one / an" and "said" used in this specification also include plural forms, as long as the context is not clearly indicated as singular. In addition, it should be understood that when the terms "have (has)" and / or "include (having)" are used in this specification, it is meant that there are described features, integers, steps, operations, elements and / or components, but it is not excluded that there are or add one or more other features, integers, steps, operations, elements, components and / or their combinations. The term "and / or" used herein includes any one or more combinations of the listed elements.

[0054] First refer to Figure 1 .

[0055] Figure 1The first bending vibration mode G of the eccentric shaft 23 with external double-point support is schematically shown. It should be noted that in a traditional dual-bearing system, that is, when bearings 3 and 4 are respectively provided at both ends of the shaft 23, the first bending vibration mode G of the shaft is formed, and its vibration node S is only located at or beyond the range of bearing positions 3 and 4. Figure 1 As shown, the arrangement of this example has two vibration nodes S.

[0056] "Vibration modes" and "vibration nodes" are terms used in the field of (mechanical) vibrations or machine dynamics. A vibration mode or vibration mode describes the shape or configuration of an elastic structure's motion at its natural frequency. In addition to bending vibrations, there are also torsional vibrations, i.e., the vibration of a shaft about its axis of rotation, or a combination of these.

[0057] When such systems are excited, significant resonances may form, causing the entire system to exhibit poor NVH characteristics. NVH (noise, vibration, and harshness) is generally a general term for acoustic behavior.

[0058] To significantly shift this natural mode to a non-critical excitation range, the shaft, bearing, and housing stiffness must be significantly increased. However, due to structural space limitations and the compressor's surrounding conditions, the effectiveness of such stiffness enhancement measures is very limited.

[0059] As mentioned above, the core issue is that the development of bending vibration resonance can significantly degrade acoustic performance. The intensity of the system's resonance excitation depends primarily on the following factors: excitation frequency, excitation amplitude, system damping, excitation location, and / or vibration form. Due to the inherent characteristics of the system, the first four factors are difficult to effectively control.

[0060] According to the present invention, the eccentric shaft in a radial piston compressor is supported by at least three bearings, preferably three bearings. In other words, by selectively selecting the number of bearings, their position, and / or their stiffness, the vibration pattern is influenced so that the vibration nodes are located as close as possible to the excitation locations.

[0061] To this end, Figure 2The figure schematically shows the first bending vibration form G of the shaft 23 with three-point support, and its vibration node S is close to the excitation position O. In theory, if the vibration node S completely coincides with the excitation position O, no resonance will occur. However, in actual applications, due to non-freely set factors such as structural space, bearing position or cylinder arrangement, eccentricity (eccentric height / offset), those skilled in the art configure the compressor to: bring the vibration node S as close as possible to the excitation position or the position where the load force is introduced. As shown in the figure, the shaft 23 in this embodiment has a first bearing 3, a second bearing 4 and a third bearing 5. The load force introduction position O or the excitation position O in the schematic diagram is marked in the form of a dot, representing the force acting on the shaft 23.

[0062] The following will refer to Figures 3 to 6 These figures illustrate an embodiment of a radial piston compressor according to the present invention. In particular, the structure of the radial piston compressor is adjusted so that the third bearing position, in particular the corresponding stiffness adjustment of the mating bearing shaft and the housing components, produces the above-described effect.

[0063] Figure 3 A sectional view of the eccentric shafts 23 , 24 together with the rotor 12 of the radial piston compressor according to the invention is shown.

[0064] The eccentric shafts 23 and 24 mainly include a drive shaft 23 and an eccentric disc 24. An eccentric bearing 27, such as a needle bearing, can be mounted on the eccentric disc 24.

[0065] It can also be seen that bearings 3, 4, and 5, specifically ball bearings, are mounted at three different axial positions on the eccentric shafts 23 and 24. Specifically, the first bearing 3 is located in the region of one end of the eccentric shaft, the second bearing 4 is located approximately in the middle of the eccentric shaft, and the third bearing 5 is located at the other end of the eccentric shaft. In particular, the second bearing 4 is arranged between the eccentric disc 24 and the rotor 12. Furthermore, in the bearing arrangement thus formed for the shaft 23, the eccentric disc 24 is located axially between the two bearings, bearing 3 and bearing 4. Figure 3 The bending vibration form G of the shaft 23 shown by the dotted line in the figure forms a vibration node S due to the existence of three bearing positions 3, 4, and 5 and their arrangement relationship. The vibration node S is adjacent to the load introduction position O in its axial position, particularly on the rotation axis D of the shaft 23.

[0066] Figure 4 Detailed description of the drawings A cross-sectional side view of a radial piston compressor embodiment of the present invention is shown in FIG.

[0067] The radial piston compressor mainly includes a drive device 1 and a compressor unit 2 in addition to the eccentric shafts 23 and 24 .

[0068] The drive device 1 mainly comprises a drive housing 11 and a rotor 12. To maintain clarity of the diagram, the stator is not shown here. Therefore, the drive device 1 is preferably mainly configured in the form of an electric motor.

[0069] The compressor unit 2 mainly includes at least one (preferably multiple) piston / working chamber combinations 21, 22 arranged around eccentric shafts 23, 24. Preferably, the piston / working chamber combinations 21, 22 extend radially from the eccentric shafts 23, 24. The piston / working chamber combinations 21, 22 are arranged in a compressor housing 25, also called a cylinder housing, or the working chamber 21 can be configured to be at least partially formed by the compressor housing 25. It can be further set that a compressor housing cover 26 is provided on one side of the compressor housing 25. The compressor housing cover 26 can be disassembled for maintenance purposes, for example, and / or constitutes a part of the working chamber 21. In the axial direction, the housing components are arranged in the following order: compressor housing cover 26, compressor housing 25, drive housing 11, wherein Figure 4 In the illustrated configuration, the compressor housing 25 does not extend to the outside of the compressor. The housing components can be detachably connected by screws. The housing of the radial piston compressor can be composed of a drive housing 11, a compressor housing 25, and a compressor housing cover 26.

[0070] The piston / working chamber combination itself comprises a working chamber 21 and a piston 22 which is reciprocating in the working chamber 21. By the reciprocating movement of the piston 22 in the working chamber 21, the fluid contained in the working chamber 21, such as a refrigerant, in particular CO2, can be compressed.

[0071] The drive device 1 rotates the drive shaft 23, causing the eccentric disk 24 to strike the piston 22, particularly the piston base. This forces the piston 22 within the working chamber 21, away from the eccentric shaft. The piston 22 is thus driven by the eccentric shaft. A piston guide ring 29 may also be provided to contact the piston 22 and push it back toward the eccentric shafts 23 and 24.

[0072] As mentioned above, the eccentric disc 24 can be equipped with an eccentric bearing 27. The piston 22, in particular its bottom, can also be equipped with a transmission element 28. The transmission element 28 can be made of a different material from the piston 22, such as plastic or a metal alloy that is particularly suitable for frequent contact with the eccentric disc 24 or the eccentric bearing 27.

[0073] Other components, such as valves, channels, etc., are not described in further detail here. However, the operating principle of a radial piston compressor is known to those skilled in the art.

[0074] As mentioned above, according to the present invention, it is provided that in the radial piston compressor the eccentric shaft is supported by at least three bearings, preferably three bearings 3 , 4 , 5 .

[0075] Figure 4 The figure shows an embodiment of a radial piston compressor according to the present invention, in which eccentric shafts 23 and 24 are supported in the radial piston compressor via three bearings 3, 4, and 5. In this embodiment, the first bearing 3 is disposed in the compressor housing cover 26, the second bearing 4 is disposed in the compressor housing 25, and the third bearing 5 is disposed in the drive housing 11.

[0076] Figure 5 Another embodiment of a radial piston compressor according to the present invention is shown, in which eccentric shafts 23 and 24 are supported in the radial piston compressor via three bearings 3, 4, and 5. In this embodiment, the first and second bearings 3 and 4 are disposed in the compressor housing 25 or cylinder housing 25, and the third bearing 5 is disposed in the drive housing 11. Therefore, bearings 3 and 4 are axially arranged on either side of the piston 22 or the working chamber 21. This places bearings 3 and 4 axially close to the load introduction point O, providing optimal support for the shaft 23. The housing of the radial piston compressor can be composed of the drive housing 11, the compressor housing 25, and the compressor housing cover 26.

[0077] Figure 6 Another embodiment of a radial piston compressor according to the present invention is shown, in which the eccentric shafts 23 and 24 are supported in the radial piston compressor by three bearings 3, 4, and 5. In this embodiment, the first bearing 3 and the second bearing 4 are arranged in the compressor housing 25, and the third bearing 5 is arranged in the drive housing 11. It is also provided that the eccentric shafts 23 and 24 are composed of multiple parts in the axial direction. Preferably, it includes a first axial part 231 and at least one second part 232, or only includes one second part 232. In this case, the eccentric shaft can also be called a combined eccentric shaft. The housing of the radial piston compressor can be composed of a drive housing 11, a compressor housing 25 and a compressor housing cover 26. As Figure 6 As shown, in this embodiment the compressor housing 25 extends to its outer side or outer shell surface. Figure 6 It can also be seen that the eccentric shaft is guided in the axial direction by the fixing ring 30. The advantage of this design is that the bearing does not need to bear any axial force.

[0078] exist Figure 7 In FIG. 1 , a radial piston compressor according to the invention is shown in a sectional plan view, in particular to illustrate the arrangement of a plurality of piston / working chamber combinations 21, 22, in this example six. For clarity of the illustration, only one piston / working chamber combination is labeled with the reference numerals 21, 22.

[0079] The radial piston compressor according to the present invention can be further characterized by the following features:

[0080] Preferably, the bearings 3 , 4 , 5 can be provided as sliding bearings or rolling bearings, in particular cylindrical roller bearings or ball bearings.

[0081] Preferably, provision can be made for one of the bearings 3 , 4 , 5 to be designed as an axial bearing.

[0082] Preferably, the bearings 3 , 4 , 5 can be installed in the housings 11 , 25 , 26 by press-fitting.

[0083] Preferably, it can be provided that the eccentric shaft is guided in the axial direction by means of the fixing ring 30. Therefore, the bearings 3, 4 and 5 do not need to bear any axial forces.

Claims

1. A radial piston compressor comprising: - a compressor unit (2) and a drive device (1) for driving the compressor unit (2), wherein: The compressor unit (2) comprises at least one, preferably a plurality of, piston / working chamber combinations (21, 22) arranged radially around an eccentric shaft (23, 24), wherein: - Each piston / working chamber combination (21, 22) comprises a working chamber (21) with a piston (22), wherein the piston (22) is displaceably accommodated in the working chamber, and the piston (22) is driven by an eccentric shaft (23, 24), Its characteristics are: The eccentric shaft (23, 24) is rotatably supported in the radial piston compressor via at least three bearings, preferably three bearings (3, 4, 5).

2. The radial piston compressor according to claim 1, characterized in that The radial piston compressor comprises a drive housing (11), a compressor housing (25) and a compressor housing cover (26).

3. The radial piston compressor according to any one of the preceding claims, characterized in that The first bearing (3) is arranged in the compressor housing cover (26), the second bearing (4) is arranged in the compressor housing (25), and the third bearing (5) is arranged in the drive housing (11).

4. The radial piston compressor according to any one of the preceding claims, characterized in that The first bearing (3) and the second bearing (4) are arranged in a compressor housing (25), and the third bearing (5) is arranged in a drive housing (11).

5. The radial piston compressor according to any one of the preceding claims, characterized in that The shaft (23) forms a vibration node (S) due to the three bearing positions (3, 4, 5) and their arrangement, wherein the vibration node (S) is arranged adjacent to the load introduction position (O) in its axial position.

6. The radial piston compressor according to any one of the preceding claims, characterized in that The bearings (3, 4, 5) are designed as sliding bearings or rolling bearings, in particular as cylindrical roller bearings or ball bearings.

7. The radial piston compressor according to any one of the preceding claims, characterized in that The individual bearings (3, 4 or 5) are configured as axial bearings.

8. The radial piston compressor according to any one of the preceding claims, characterized in that The bearings (3, 4, 5) are installed in the housing by press-fitting.

9. The radial piston compressor according to any one of the preceding claims, characterized in that The eccentric shaft is axially guided by a fixing ring (30).

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