Positive-displacement machine

Abstract

The invention relates to a positive-displacement machine in accordance with the spiral principle, in particular a scroll-type compressor, with a. a housing (10), b. an orbiting displacement spiral (11) and a mating spiral (12) which engage into one another in such a way that variable compression chambers (13) are formed between the displacement spiral (11) and the mating spiral (12), in order to receive and to compress an operating medium which flows through an operating medium circuit, c. a drive shaft (14) which is drive-connected to the displacement spiral (11), and d. an anti-rotation mechanism (15) for guiding the displacement spiral (11). It is characterized in that a bearing (16) of the drive shaft (14) is arranged in a multiple-part bearing plate (17), the bearing plate (17) comprising a first housing portion (18) with a bearing seat (19) for the bearing (16), and a second housing portion (20) which is connected to the first housing portion (18), wherein the second housing portion (20) projects radially inwards beyond an inner wall (22) of the first housing portion (18).

Description

[0001] Displacement machine

[0002] Description

[0003] The invention relates to a displacement machine according to the spiral principle with the features of the preamble of patent claim 1. Such a displacement machine is known, for example, from DE 10 2016 118 525 A1.

[0004] DE 10 2016 118 525 A1 describes a positive displacement machine based on the scroll principle, also known as a scroll compressor. The positive displacement machine has a housing in which a bearing is arranged that supports a drive shaft. The housing has a bearing seat for the bearing and a receiving space for a balancing mass connected to the drive shaft. The drive shaft engages eccentrically in an orbiting displacement spiral, which is in spiral engagement with a counter-spiral. The orbiting movement of the displacement spiral, caused by the eccentric connection to the drive shaft, creates variable compression chambers between the displacement spiral and the counter-spiral. During operation, the compression chambers receive and compress a working fluid flowing through a working fluid circuit.For this purpose, an anti-rotation mechanism is provided, which engages with openings in the base of the displacement spiral and prevents the displacement spiral from rotating freely. This guides the displacement spiral and achieves the orbiting motion. The basic principle of such displacement machines is known to those skilled in the art.

[0005] DE 10 2016 118 525 A1 has recognized that it is advantageous if the anti-rotation mechanism is not connected directly to the housing, but rather to an annular sliding plate located between the housing and the displacement spiral. The sliding plate serves, on the one hand, to increase the space available for the drive shaft bearing and the balancing mass. On the other hand, advantageous material combinations between the anti-rotation mechanism and the sliding plate are possible. However, the known housing design is complex.

[0006] The object of the invention is to provide a displacement machine based on the spiral principle, which is of simple construction and further improved with regard to the installation space.

[0007] This object is achieved according to the invention by the subject matter of patent claim 1.

[0008] Specifically, the task is solved by a positive displacement machine based on the scroll principle, which comprises a housing, an orbiting displacement scroll, and a counter scroll. The positive displacement machine is preferably a scroll compressor.

[0009] The displacement scroll and the counter scroll mesh in such a way that variable compression chambers are formed between the displacement scroll and the counter scroll to accommodate and compress a working fluid flowing through a working fluid circuit. The positive displacement machine has a drive shaft that is drivingly connected to the displacement scroll and an anti-rotation mechanism for guiding the displacement scroll. The invention is characterized in that a bearing of the drive shaft is arranged in a multi-part bearing plate, wherein the bearing plate comprises a first housing section with a bearing seat for the bearing and a second housing section. The second housing section is connected to the first housing section.

[0010] The second housing section projects radially inward beyond an inner wall of the first housing section.

[0011] In contrast to the prior art, the bearing is arranged in the multi-part bearing plate according to the invention. This has the advantage that the housing of the positive displacement machine is simple in design because the bearing seat is formed in the bearing plate. This reduces the wall thickness of the housing. In addition, there are manufacturing advantages because the multi-part bearing plate can be pre-assembled with the bearing.

[0012] Another advantage of the multi-part bearing plate is the separation of functions. The first housing section with the bearing seat and the second housing section can be optimized separately for their respective functions. For example, the second housing section can be optimally adapted with regard to the anti-rotation mechanism and / or the sliding properties, without being restricted to these. Other optimization measures are possible.

[0013] According to the invention, the second housing section protrudes radially inward beyond an inner wall of the first housing section. This increases the installation space because the first housing section can be designed with a correspondingly larger inner diameter while maintaining the dimensions that are based on the orbiting displacement spiral. The invention also facilitates the assembly of the bearing and the assembly of other components because the bearing plate can be split for assembly.

[0014] In the context of the invention, "radially inwardly projecting" means that the second housing section forms a projection that extends radially relative to the first housing section. For example, in an embodiment in which the second housing section is formed as a ring, this means that the inner diameter of the ring is smaller than the inner diameter of the first housing section, without the invention being limited to this embodiment.

[0015] Further embodiments of the invention are specified in the subclaims.

[0016] For example, the second housing section can protrude radially inward over the bearing seats and / or over a receiving space for a compensating device. This has the advantage that the inner diameter of the bearing seat and / or the inner diameter of the receiving space for the compensating device can be made correspondingly larger. This allows for the use of large bearings for the drive shaft and large masses for the compensating device.

[0017] In a preferred embodiment, at least 20%, in particular at least 30%, of the second housing section protrudes freely inward. This achieves a correspondingly large increase in installation space in the first housing section. The upper limit of the aforementioned range of at least 20% or at least 30% is determined by the contact surface of the second housing section on the first housing section and the respective wall thicknesses.

[0018] Preferably, the second housing section forms a ring whose inner diameter is smaller than the inner diameter of the first housing section. The inner diameter of the second housing section can be smaller than the maximum inner diameter of the first housing section. In other words, the second housing section protrudes radially inward completely beyond the first housing section.

[0019] It is also possible for the second housing section to have an inner diameter that is smaller in some sections than the inner diameter of the first housing section. This is the case, for example, if the first housing section has different inner diameters in the axial direction. In this case, it is sufficient for the second housing section to have an inner diameter that is smaller than at least one of the inner diameter sections of the first housing section, preferably the inner diameter section of the first housing section that directly adjoins the second housing section.

[0020] In a preferred embodiment, the second housing section forms a sliding surface for the displacement spiral. This has the advantage that the orbiting movement of the displacement spiral occurs with as little friction as possible.

[0021] Conveniently, the first housing section has a cylindrical inner wall, at least in sections. This section is intended, for example, for the bearing seat.

[0022] The first housing section can have a stepped inner wall or an inner wall with a constant inner diameter. With a stepped inner wall, components with different outer diameters, such as the bearing and the compensating means, can be arranged in the first housing section. Regarding the relationship between the inner diameter of the second housing section and the maximum inner diameter of the first housing section, reference is made to the above explanations. The design with the inner wall with a constant inner diameter has the advantage of being simple to manufacture. In both cases, a cylindrical geometry of the inner wall is preferred.

[0023] In a further preferred embodiment, the second housing section is connected to the anti-rotation mechanism in a force-transmitting manner. For this purpose, the second housing section has a correspondingly thick wall, which the expert selects depending on the forces to be transmitted by the anti-rotation mechanism. This embodiment has the advantage that coordinated material pairings can be used for the anti-rotation mechanism and the second housing section. Furthermore, this embodiment has the advantage of a compact design.

[0024] Preferably, the anti-rotation mechanism is arranged in the radially inwardly projecting region of the second housing section. This allows for a space-saving arrangement of the anti-rotation mechanism.

[0025] Conveniently, the anti-rotation mechanism comprises pins which engage in corresponding openings in the distributor spiral for guiding the latter, wherein the pins are inserted, in particular fitted, into the second housing section and connected thereto.

[0026] If at least the first housing section of the bearing plate is connected, in particular screwed, to the housing of the displacement machine, a material separation from the housing of the compressor machine and a completely internal bearing plate is possible.

[0027] The invention will be described in more detail below using exemplary embodiments with reference to the attached schematic drawings.

[0028] Fig. 1 shows the longitudinal section of a displacement machine in the region of the multi-part bearing plate according to a first embodiment of the invention and Fig. 2 shows the longitudinal section of a displacement machine according to a second embodiment of the invention.

[0029] Fig. 1 shows a section of the positive displacement machine in the area between the low pressure side and the high pressure side.

[0030] On the low-pressure side, a drive shaft 14 is arranged in the housing 10. The drive shaft 14 is driven, for example, by an electric motor (not shown) or another drive. The electric motor can be arranged in the housing 10. Other arrangements or drive concepts are possible.

[0031] On the high-pressure side, an orbiting displacement scroll 11 and a stationary counter-scroll 12 are arranged in the housing 10. These are in spiral engagement with each other and form variable compression chambers 13, the volume of which changes due to a relative movement between the orbiting displacement scroll 11 and the stationary counter-scroll 12. An anti-rotation mechanism 15 is provided to guide the displacement scroll 11 on an orbiting path. The anti-rotation mechanism 15 engages the displacement scroll 11 and, together with the eccentric connection of the displacement scroll 11 and the drive shaft 14, causes the orbiting movement of the displacement scroll 11. During operation, a working fluid flows into the variable compression chambers 13 and is compressed there. The general operating principle of such positive displacement machines is known to those skilled in the art.

[0032] In Fig. 1, it is clearly visible that a multi-part bearing plate 17 is arranged in the housing 10. The bearing plate 17 serves, on the one hand, to accommodate the components required for the moving parts and, on the other hand, to separate the low-pressure side and the high-pressure side of the positive displacement machine.

[0033] The bearing plate 17 is arranged completely in the housing 10, ie inside.

[0034] Specifically, in the present embodiment, the bearing plate 17 is constructed in two parts and has a first housing section 18 and a second housing section 20. Additional housing sections of the bearing plate 17 are possible. The term housing section 18, 20 means that the bearing plate 17 forms a housing unit within the superordinate housing 10 of the positive displacement machine and itself accommodates internal components.

[0035] The term "multi-part bearing plate 17" means that the bearing plate 17 is divided, at least during assembly, into several separate parts, namely the housing sections 18, 20. The bearing plate 17 can be referred to as an assembled bearing plate 17, which is composed of several housing sections 18, 20.

[0036] The housing sections 18, 20 are detachably connected, in particular detachably connected to the housing 10.

[0037] A bearing 16 of the drive shaft 14 is arranged in the bearing plate 17, as shown in Fig. 1. The bearing 16 can be a rolling bearing, for example. Other bearing types are possible. The bearing 16 can be referred to as the drive bearing or the main bearing of the drive shaft 14.

[0038] Specifically, the bearing 16 is arranged in the first housing section 18, which has a bearing seat 19 for the bearing 16.

[0039] The second housing section 20 is arranged on the high-pressure side of the first housing section 18 in the axial direction of the displacement machine and forms the high-pressure side end of the bearing plate 17. The axial direction of the displacement machine is defined by the longitudinal axis of the drive shaft 14.

[0040] The second housing section 20 is connected to the first housing section, in particular detachably connected. Various connection types are possible, such as the screw connection shown in Fig. 1.

[0041] The second housing section 20 has a sliding surface 21 on the high-pressure side. During operation, the displacer spiral 11 slides on the sliding surface 21 and is sealed against the sliding surface 21. During operation, the displacer spiral 11 moves on an orbiting path relative to the sliding surface 21 or to the second housing section 20. Fig. 1 clearly shows that the second housing section 20 protrudes radially inward beyond an inner wall 22 of the first housing section 18. The radial projection of the second housing section 20 means that the first housing section 18 can be enlarged. The additional space in the area of ​​the first housing section 18 can be used to arrange a large bearing 16 in the bearing plate 17 or to design other components in the first housing section 18 to be large.

[0042] In the embodiment according to Fig. 1, the radial projection or overhang is achieved in that the second housing section 20 has an inner diameter which is smaller than the inner diameter of the first housing section 18.

[0043] The expression "radially inwardly projecting" does not necessarily mean that the two housing sections 18, 20 must be rotationally symmetrical. Other geometries are possible which result in the second housing section 20 projecting inward beyond an inner wall of the first housing section 18 and thereby leading to an increase in installation space in the region of the first housing section 18.

[0044] In the embodiment shown in Fig. 1, the second housing section 20 protrudes radially inward beyond the entire inner wall 22 of the first housing section 18. Specifically, the second housing section 20 protrudes radially inward beyond the bearing seat 19 and a receiving space 23 for a compensating means 24. The receiving space 23 is also formed in the first housing section 18. The compensating means 24 serves as a compensating mass due to the eccentric mounting of the displacement spiral 11.

[0045] In the exemplary embodiment according to Fig. 1, the bearing seat 19 and the receiving space 23 are functionally, not structurally, separate. The inner wall 22 of the first housing section 18 is cylindrical. The inner diameter of the bearing seat 19 and the receiving space 23 is the same. This results in the second housing section 20 protruding radially inward beyond both the bearing seat 19 and the receiving space 23. Other arrangements are possible. The projection amounts to at least 20%, in particular at least 30% of the second housing section 20. This means that at least 20% of the area of ​​the second housing section, in particular at least 30% of the area of ​​the second housing section 20, protrudes freely inward beyond the first housing section 18. The upper limit of this area is determined by the support surface required for the connection between the two housing sections 18, 20.

[0046] In the embodiment according to Fig. 1, the second housing section 20 is designed as a ring whose inner diameter is smaller than the inner diameter of the first housing section 18.

[0047] The first housing section 18 is cylindrical with a bottom arranged on the low-pressure side. A through-opening for the drive shaft 18 is formed in the bottom, which is sealed against the drive shaft 18 by a shaft seal. The bearing 16 or the corresponding bearing seats 19 are arranged or formed at the bottom-side axial end of the first housing section 18.

[0048] The receiving space 23 for the compensating means 24 is formed between the bearing 16 and the free projection of the second housing section 20.

[0049] The high-pressure end of the first housing section 18 is open in the axial direction. In the assembled state, the high-pressure end is at least partially closed by the second housing section 20.

[0050] As shown in Fig. 1, the second housing section 20 is connected to the anti-rotation mechanism 15 in a force-transmitting manner. The anti-rotation mechanism 15 has a plurality of pins 25 that engage in corresponding openings 26 in the displacement spiral 11, specifically in the base of the displacement spiral 11. The pins 25 serve to guide the displacement spiral 11 on an orbiting path. The pins 25 are fitted into the second housing section 20, specifically into the wall of the ring that forms the second housing section 20. The pins 25 protrude axially beyond the sliding surface 21. The wall thickness of the second housing section 20 is dimensioned such that a force-transmitting connection with the pins 25 is possible. This has the advantage that no connection to the first housing section 18 or to the housing 10 is required for fastening the pins 25 or, in general, the anti-rotation mechanism 15.The pins 25 and the second housing portion 20 are made of the same or similar material, so there are little or no differences in the coefficient of thermal expansion of these parts.

[0051] The pins 25 are arranged in the radially inwardly projecting region of the second housing section 20, namely radially inwardly so far as to engage in the corresponding openings 26 in the displacement spiral 11.

[0052] The multi-part bearing plate 17 is generally considered a separate unit that is connected, for example, by screwing, to the housing 10. Other connections are possible. The bearing plate 17 is completely enclosed within the housing 10.

[0053] The connection between the bearing plate 17 and the housing 10 can be made, for example, by arranging and fastening the bearing plate 17 between the housing 10 and the stationary counter-spiral 12.

[0054] Specifically, as shown in Fig. 1, an outer flange of the bearing plate 17 is clamped between a housing shoulder of the housing 10 and the stationary counter-spiral 12. For this purpose, a screw connection is provided that connects the housing shoulder and the counter-spiral 12 and penetrates the outer flange. In Fig. 1, the internal thread of the screw connection is formed in the counter-spiral 12. The internal thread can also be formed in the housing 10 (see Fig. 2). This connection of the bearing plate 17 is space-saving and compact. Other connection types are possible.

[0055] Fig. 2 shows a further embodiment that essentially corresponds to the first embodiment. Regarding the identical features, reference is made to the explanations for Fig. 1. One difference concerns the inner contour of the first housing section 18. In the embodiment according to Fig. 2, the first housing section 18 has different inner diameters of the bearing seat 19 and the receiving space 23. The inner contour of the first housing section 18 is stepped.

[0056] In Fig. 2 it can be seen that the inner diameter of the second housing section 20 is smaller than the inner diameter of the receiving space 23. The inner diameter of the bearing seat 18 is smaller than the inner diameter of the receiving space 23 but still larger than the inner diameter of the second housing section 20.

[0057] The inner diameter of the second housing section 20 is therefore smaller than the two inner diameters of the first housing section 18. A partial increase in installation space with regard to the receiving space 23 could be achieved if the inner diameter of the second housing section 20 is only smaller than the inner diameter of the receiving space 23.

[0058] The principle that the second housing section protrudes radially inwards over the first housing section 18 is also given here.

[0059] The multi-part bearing plate 17 allows for an increase in the installation space for the bearing 16 and the compensating element 24. These can therefore be designed correspondingly larger. Furthermore, the bearing plate 17 can be preassembled with the bearing 16, the drive shaft 14, and the compensating element 24, thus facilitating production.

[0060] List of reference symbols

[0061] Housing 10

[0062] Displacement spiral 11

[0063] Counter spiral 12

[0064] Compression chambers 13

[0065] Drive shaft 14

[0066] Anti-rotation mechanism 15 Bearing 16

[0067] Bearing plate 17 first housing section 18

[0068] Bearing seat 19 second housing section 20

[0069] Sliding surface 21

[0070] Interior wall 22

[0071] Recording Room 23

[0072] Leveling agent 24 Pins 25

[0073] Openings 26

Claims

Claims 1. Positive displacement machine according to the spiral principle, in particular a scroll compressor, with a. a housing (10), b. an orbiting displacement spiral (11) and a counter spiral (12), which engage with each other in such a way that variable compression chambers (13) are formed between the displacement spiral (11) and the counter spiral (12) in order to receive and compress a working medium flowing through a working medium circuit, c. a drive shaft (14) which is drivingly connected to the displacement spiral (11), and d. an anti-rotation mechanism (15) for guiding the displacement spiral (11), characterized in that a bearing (16) of the drive shaft (14) is arranged in a multi-part bearing plate (17), wherein the bearing plate (17) comprises a first housing section (18) with a bearing seat (19) for the bearing (16) and a second housing section (20) which is connected to the first housing section (18), wherein the second housing section (20) projects radially inwards beyond an inner wall (22) of the first housing section (18).

2. Displacement machine according to claim 1, characterized in that the second housing section (20) projects radially inwards over the bearing seat (19) and / or over a receiving space (23) for a compensating means (24).

3. Displacement machine according to one of the preceding claims, characterized in that the second housing section (20) forms a ring whose inner diameter is smaller than the inner diameter of the first housing section (18).

4. Displacement machine according to one of the preceding claims, characterized in that the second housing section (20) forms a sliding surface (21) for the displacement spiral (11) 5. Displacement machine according to one of the preceding claims, characterized in that the first housing section (18) has at least in sections a cylindrical inner wall (22).

6. Positive displacement machine according to one of the preceding claims, characterized in that the first housing section (18) has a stepped inner wall (22) or an inner wall (22) with a constant inner diameter.

7. Displacement machine according to one of the preceding claims, characterized in that the second housing section (20) is connected to the anti-rotation mechanism (15) in a force-transmitting manner.

8. Displacement machine according to one of the preceding claims, characterized in that the anti-rotation mechanism (15) is arranged in the radially inwardly projecting region of the second housing section (20).

9. Positive displacement machine according to one of the preceding claims, characterized in that the anti-rotation mechanism (15) has pins (25) which engage in openings (26) in the displacement spiral (11) for guiding the latter, the pins (25) being inserted into the second housing section (20) and connected thereto.

10. Displacement machine according to one of the preceding claims, characterized in that at least the first housing section (18) of the bearing plate (17) is connected, in particular screwed, to the housing (10).

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