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, b. an orbiting displacement spiral and a mating spiral which engage into one another in such a way that variable compression chambers are formed between the displacement spiral and the mating spiral, in order to receive and to compress an operating medium which flows through an operating medium circuit, c. a drive shaft which is drive-connected to the displacement spiral, and d. an anti-rotation mechanism for guiding the displacement spiral. It is characterized in that a bearing of the drive shaft is arranged in a multiple-part bearing plate, the bearing plate comprising a first housing portion with a bearing seat for the bearing, and a second housing portion which is connected to the first housing portion, wherein the second housing portion projects radially inwards beyond an inner wall of the first housing portion.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a National Stage Application of International Application No. PCT / EP2023 / 079548, filed on Oct. 24, 2023, which claims benefit of priority to German Patent Application No. 102022134443.6, filed on Dec. 21, 2022 which applications are incorporated herein by reference in their entirety. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.TECHNICAL FIELD

[0002] The invention relates to a positive-displacement machine according to the spiral principle. Such a positive-displacement machine is known from DE 10 2016 118 525 A1, for example.BACKGROUND

[0003] DE 10 2016 118 525 A1 describes a positive-displacement machine according to the spiral principle, which is also known as a scroll-type compressor. The positive-displacement machine has a housing that incorporates a bearing in which a drive shaft is arranged. The housing has a bearing seat for the bearing, as well as a receiving space for a leveling compound, which is connected with the drive shaft. The drive shaft eccentrically engages into an orbiting displacement spiral, which is spirally engaged with a mating spiral. An orbiting motion of the displacement spiral caused by the eccentric connection with the drive shaft produces variable compression chambers between the displacement spiral and the mating spiral. During operation, the compression chambers receive a working fluid flowing through a working fluid circuit and compress it. Provided for this purpose is an anti-rotation mechanism, which engages into openings in the floor of the displacement spiral and prevents the displacement spiral from rotating freely. In this way, the displacement spiral is guided and the orbiting motion is achieved. The basic principle of such positive-displacement machines is known to the expert.

[0004] DE 10 2016 118 525 A1 recognized that it is advantageous for the anti-rotation mechanism to not be directly connected with the housing, but rather with an annular sliding plate, which is located between the housing and the displacement spiral. The sliding plate is used on the one hand to enlarge the installation space available for the drive shaft bearing and for the leveling compound. On the other hand, advantageous material pairings between the anti-rotation mechanism and the sliding plate are possible. The known housing construction is complex, however.

[0005] The object of the invention is to provide a positive-displacement machine according to the spiral principle, which has a simple design and is further improved with respect to the installation space.

[0006] Specifically, the object is achieved by a positive-displacement machine according to the spiral principle, which has a housing, an orbiting displacement spiral, and a mating spiral. The positive-displacement machine is preferably a scroll-type compressor.

[0007] The displacement spiral and the mating spiral engage into each other in such a way as to form variable compression chambers between the displacement spiral and the mating spiral, in order to receive and compress a working fluid flowing through a working fluid circuit. The positive-displacement machine has a drive shaft, which is drive-connected with the displacement spiral, and an anti-rotation mechanism for guiding the displacement spiral. The invention is characterized in that a bearing of the drive shaft is arranged in a multiple-part bearing plate, wherein the bearing plate comprises a first housing portion with a bearing seat for the bearing and a second housing portion. The second housing portion is connected with the first housing portion. The second housing portion projects radially inward over an inner wall of the first housing portion.

[0008] As opposed to prior art, the bearing according to the invention is arranged in the multiple-part bearing plate. The advantage to this is 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. There are also manufacturing advantages, because the multiple-part bearing plate can be preassembled with the bearing.

[0009] Another advantage to the multiple-part bearing plate is the functional separation. The first housing portion with the bearing seat and the second housing portion can be separately optimized with regard to their respective functions. For example, the second housing portion can be optimally adjusted with regard to the anti-rotation mechanism and / or to the sliding properties, without being limited thereto. Other optimization measures are possible.

[0010] According to the invention, the second housing portion projects radially inward over an inner wall of the first housing portion. This results in an enlarged installation space, because the first housing portion can be configured with a correspondingly larger inner diameter, while retaining the dimensions oriented to the orbiting displacement spiral. The invention further simplifies the assembly of the bearing and the assembly of other fixtures, since the bearing plate can be divided for assembly purposes.

[0011] In conjunction with the invention, projecting radially inward means that the second housing portion forms a projection that extends in a radial direction in relation to the first housing portion. For example, in an embodiment where the second housing portion is designed like a ring, this means that the inner diameter of the ring is smaller than the inner diameter of the first housing portion, without the invention being limited to this embodiment.

[0012] The second housing portion can project radially inward over the bearing seats and / or over a receiving space for a leveling agent. The advantage to this is that the inner diameter of the bearing seat and / or the inner diameter of the receiving space for the leveling agents can be made correspondingly larger. As a result, large bearings can be used for the drive shaft, and large masses can be used for the leveling agent.

[0013] In a preferred embodiment, at least 20%, in particular at least 30%, of the second housing portion freely projects inwardly. This yields a correspondingly large additional installation space in the first housing portion. The upper limit of the aforementioned area of at least 20% or at least 30% is determined by the support surface of the second housing portion on the first housing portion and the respective wall thicknesses.

[0014] The second housing portion preferably forms a ring, the inner diameter of which is smaller than the inner diameter of the first housing portion. The inner diameter of the second housing portion can here be smaller than the maximum inner diameter of the first housing portion. In other words, the second housing portion projects radially inward completely over the first housing portion.

[0015] It is also possible for the second housing portion to have an inner diameter that is sectionally smaller than the inner diameter of the first housing portion. For example, this is the case when the first housing portion has varying inner diameters in an axial direction. It is then sufficient for the second housing portion to have an inner diameter smaller than at least one of the inner diameter portions of the first housing portion, preferably than the inner diameter portion of the first housing portion that directly adjoins the second housing portion.

[0016] In a preferred embodiment, the second housing portion forms a sliding surface for the displacement spiral. The advantage to this is that the orbiting motion of the displacement spiral takes place with as little friction as possible.

[0017] It is expedient that at least portions of the first housing portion have a cylindrical inner wall. For example, this portion is provided for the bearing seat.

[0018] The first housing portion can have a stepped inner wall or an inner wall with a constant inner diameter. Given a stepped inner wall, fixtures with a varying outer diameter can be arranged in the first housing portion, for example the bearing and the leveling agent. Reference is made to the above statements with respect to the ratio between the inner diameter of the second housing portion and the maximum inner diameter of the first housing portion. The embodiment with the inner wall having a constant inner diameter has the advantage of being easy to manufacture. In both cases, a cylindrical geometry is preferred for the inner wall.

[0019] In another preferred embodiment, the second housing portion is connected in a force-transmitting manner with the anti-rotation mechanism. For this purpose, the second housing portion has a correspondingly strong wall, which the expert selects as a function of the forces of the anti-rotation mechanism to be transmitted. The advantage to this embodiment is that coordinated material pairings of the anti-rotation mechanism and the second housing portion can be used. In addition, this embodiment offers the advantage of a compact design.

[0020] The anti-rotation mechanism is preferably arranged in the radially inwardly projecting area of the second housing portion. This yields a space-saving arrangement of the anti-rotation mechanism.

[0021] The anti-rotation mechanism expediently has pins, which engage into corresponding openings in the distribution spiral for guiding the latter, wherein the pins are introduced, in particular fitted, into the second housing portion, and connected with it.

[0022] Connecting, in particular screwing, at least the first housing portion of the bearing plate with the housing of the positive-displacement machine enables a material separation from the housing of the compression machine as well as a completely internal bearing plate.BRIEF DESCRIPTION OF THE FIGURES

[0023] The invention will be described in more detail below with further particulars based upon exemplary embodiments, with reference to the accompanying schematic drawings. These show:

[0024] FIG. 1 a longitudinal section of a positive-displacement machine in the area of the multiple-part bearing plate according to a first exemplary embodiment of the invention, and

[0025] FIG. 2 a longitudinal section of a positive-displacement machine according to a second exemplary embodiment of the invention.DETAILED DESCRIPTION

[0026] FIG. 1 shows a portion of the positive-displacement machine in the area between the low-pressure side and the high-pressure side.

[0027] A drive shaft 14 is arranged in the housing 10 on the low-pressure side. For example, the drive shaft 14 is driven by an electric motor (not shown) or some other drive. The electric motor can be arranged in the housing 10. Other arrangements or drive concepts are possible.

[0028] An orbiting displacement spiral 11 and a fixed mating spiral 12 are arranged in the housing 10 on the high-pressure side. The latter are spirally engaged with each other and form variable compression chambers 13, the volume of which is changed by a relative motion between the orbiting displacement spiral 11 and the fixed mating spiral 12. An anti-rotation mechanism 15 is provided for guiding the displacement spiral 11 on an orbiting path. The anti-rotation mechanism 15 engages into the displacement spiral 11 and, in conjunction with the eccentric connection of the displacement spiral 11 and the drive shaft 14, produces the orbiting motion of the displacement spiral 11. During operation, a working fluid flows into the variable compression chambers 13 and is there compressed. The general functional principle of such positive-displacement machines is known to the expert.

[0029] As readily visible on FIG. 1, a multiple-part bearing plate 17 is arranged in the housing 10. The bearing plate 17 has the function of incorporating the fixtures necessary for the moving parts on the one hand and separates the low-pressure side and the high-pressure side of the positive-displacement machine on the other hand.

[0030] The bearing plate 17 is arranged completely inside the housing 10, i.e., internally arranged.

[0031] Specifically, the bearing plate 17 has a two-part design in the present exemplary embodiment and has a first housing portion 18 and a second housing portion 20. Additional housing portions of the bearing plate 17 are possible. The term housing portion 18, 20 means that the bearing plate 17 forms a housing unit in the superordinate housing 10 of the positive-displacement machine, and itself incorporates fixtures.

[0032] The term multiple-part bearing plate 17 means that the bearing plate 17 is divided into several separate parts, specifically the housing portions 18, 20, at least during assembly. The bearing plate 17 can be referred to as an assembled bearing plate 17, which consists of several housing portions 18, 20.

[0033] The housing portions 18, 20 are detachably connected, in particular detachably connected with the housing 10.

[0034] A bearing 16 of the drive shaft 14 is arranged in the bearing plate 17, as visible on FIG. 1. For example, the bearing 16 can be a rolling bearing. Other bearing types are possible. The bearing 16 can be referred to as a driving bearing or main bearing of the drive shaft 14.

[0035] Specifically, the bearing 16 is arranged in the first housing portion 18, which for this purpose has a bearing seat 19 for the bearing 16.

[0036] The second housing portion 20 is arranged on the first housing portion 18 on the high-pressure side in an axial direction of the positive-displacement machine, and forms the high-pressure side end of the bearing plate 17. The axial direction of the positive-displacement machine is defined by the longitudinal axis of the drive shaft 14.

[0037] The second housing portion 20 is connected with the first housing portion, in particular detachably connected. Different connection types are possible, for example the screw connection shown on FIG. 1.

[0038] The second housing portion 20 has a sliding surface 21 on the high-pressure side. During operation, the displacement spiral 11 slides on the sliding surface 21, and is sealed against the sliding surface 21. During operation, the displacement spiral 11 moves relative to the sliding surface 21 or the second housing portion 20 on an orbiting path.

[0039] As readily visible on FIG. 1, the second housing portion 20 projects radially inwardly over an inner wall 22 of the first housing portion 18. Due to the radial projection of the second housing portion 20, the first housing portion 18 can be enlarged. The additional installation space in the area of the first housing portion 18 can be used for arranging a large bearing 16 in the bearing plate 17 or giving other fixtures in the first housing portion 18 a large design.

[0040] In the exemplary embodiment according to FIG. 1, the radial projection or overhang is achieved by the second housing portion 20 having an inner diameter smaller than the inner diameter of the first housing portion 18.

[0041] The term “projecting radially inward” does not necessarily mean that the two housing portions 18, 20 must be rotationally symmetrical. There are other possible geometries that cause the second housing portion 20 to project radially inward over an inner wall of the first housing portion 18, thereby leading to an enlarged installation space in the area of the first housing portion 18.

[0042] In the exemplary embodiment according to FIG. 1, the second housing portion 20 projects radially inward over the entire inner wall 22 of the first housing portion 18. Specifically, the second housing portion 20 projects radially inward over the bearing seat 19 as well as over a receiving space 23 for a leveling agent 24. The receiving space 23 is likewise formed in the first housing portion 18. The leveling agent 24 serves as a leveling compound based on the eccentric mounting of the displacement spiral 11.

[0043] The bearing seat 19 and the receiving space 23 are functionally, and not structurally separated in the exemplary embodiment according to FIG. 1. The inner wall 22 of the first housing portion 18 is cylindrical. The inner diameter of the bearing seat 19 and receiving space 23 is the same. As a result, the second housing portion 20 projects radially inward over both the bearing seat 19 and over the receiving space 23. Other arrangements are possible. The overhang measures at least 20%, in particular at least 30% of the second housing portion 20. This means that at least 20% of the surfaces of the second housing portion, in particular at least 30% of the surface of the second housing portion 20, freely projects inwardly over the first housing portion 18. The upper limit of this area is determined by the support surface required for the connection between the two housing portions 18, 20.

[0044] In the exemplary embodiment according to FIG. 1, the second housing portion 20 is designed as a ring, the inner diameter of which is smaller than the inner diameter of the first housing portion 18.

[0045] The first housing portion 18 is cylindrical in design, with a floor arranged on the low-pressure side. A passage opening is formed in the floor for the drive shaft 18 and is sealed against the drive shaft 18 by a shaft seal. The bearing 16 or the corresponding bearing seat 19 is arranged or formed on the floor-side axial end of the first housing portion 18.

[0046] The receiving space 23 for the leveling agent 24 is formed between the bearing 16 and the free overhang of the second housing portion 20.

[0047] The high-pressure side end of the first housing portion 18 is open in an axial direction. In the assembled state, the high-pressure side end is at least partially closed by the second housing portion 20.

[0048] As shown in FIG. 1, the second housing portion 20 is connected in a force-transmitting manner with the anti-rotation mechanism 15. The anti-rotation mechanism 15 has several pins 25, which engage into corresponding openings 26 in the displacement spiral 11, specifically into the floor of the displacement spiral 11. The pins 25 are used to guide the displacement spirals 11 on an orbiting path. The pins 25 are fitted into the second housing portion 20, specifically into the wall of the ring, which forms the second housing portion 20. The pins 25 axially project over the sliding surface 21.

[0049] The wall thickness of the second housing portion 20 is dimensioned in such a way as to enable a force-transmitting connection with the pins 25. The advantage to this is that no connection with the first housing portion 18 or with the housing 10 is required for attaching the pins 25 or generally the anti-rotation mechanism 15. The pins 25 and the second housing portion 20 are made out of the same or similar material, so that there are few if any differences between the heat expansion coefficients of these parts.

[0050] The pins 25 are arranged in the radially inwardly projecting area of the second housing portion 20, specifically radially inwardly to a point where they engage into the corresponding openings 26 in the displacement spiral 11.

[0051] The multiple-part bearing plate 17 is generally to be regarded as a standalone unit, which is connected, for example screwed, with the housing 10. Other connections are possible. The bearing plate 17 is completely incorporated into the housing 10.

[0052] For example, the connection between the bearing plate 17 and the housing 10 can be established by arranging and fastening the bearing plate 17 between the housing 10 and the fixed mating spiral 12.

[0053] As shown in FIG. 1, an outer flange of the bearing plate 17 is specifically clamped between a housing shoulder of the housing 10 and the fixed mating spiral 12. Provided for this purpose is a screw connection, which connects the housing shoulder and the mating spiral 12, and penetrates through the outer flange. In FIG. 1, the female thread of the screw connection is formed in the mating spiral 12. The female 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.

[0054] FIG. 2 shows another exemplary embodiment, which essentially corresponds to the first exemplary embodiment. Reference is made to the statements about FIG. 1 with respect to the matching features.

[0055] One difference relates to the inner contour of the first housing portion 18. In the exemplary embodiment according to FIG. 2, the first housing portion 18 has varying inner diameters for the bearing seat 19 and the receiving space 23. The inner contour of the first housing portion 18 is stepped.

[0056] As evident from FIG. 2, the inner diameter of the second housing portion 20 is smaller than the inner diameter of the receiving space 23. While the inner diameter of the bearing seat 18 is smaller than the inner diameter of the receiving space 23, it remains larger than the inner diameter of the second housing portion 20.

[0057] Therefore, the inner diameter of the second housing portion 20 is smaller than the two inner diameters of the first housing portion 18. A partial enlargement of the installation space with respect to the receiving space 23 could be achieved if the inner diameter of the second housing portion 20 were only smaller than the inner diameter of the receiving space 23.

[0058] The principle that the second housing portion projects radially inward over the first housing portion 18 is also given here.

[0059] The multiple-part bearing plate 17 makes it possible to increase the installation space for accommodating the bearing 16 and the leveling agent 24. For this reason, the latter can be correspondingly larger in design. In addition, the bearing plate 17 can be preassembled with the bearing 16, the drive shaft 14 and the leveling agent 24, which simplifies production.REFERENCE LISTHousing 10

[0061] Displacement spiral 11

[0062] Mating spiral 12

[0063] Compression chambers 13

[0064] Drive shaft 14

[0065] Anti-rotation mechanism 15

[0066] Bearing 16

[0067] Bearing plate 17

[0068] First housing portion 18

[0069] Bearing seat 19

[0070] Second housing portion 20

[0071] Sliding surface 21

[0072] Inner wall 22

[0073] Receiving space 23

[0074] Leveling agent 24

[0075] Pins 25

[0076] Openings 26

Claims

1. A positive-displacement machine according to the spiral principle, in particular a scroll compressor, witha. a housing,b. an orbiting displacement spiral and a mating spiral, which engage into each other in such a way as to form variable compression chambers between the displacement spiral and the mating spiral, in order to receive and compress a working fluid flowing through a working fluid circuit,c. a drive shaft, which is drive-connected with the displacement spiral, andd. an anti-rotation mechanism for guiding the displacement spiral, whereina bearing of the drive shaft is arranged in a multiple-part bearing plate, wherein the bearing plate comprises a first housing portion with a bearing seat for the bearing and a second housing portion, which is connected with the first housing portion, wherein the second housing portion projects radially inward over an inner wall of the first housing portion.

2. The positive displacement machine according to claim 1, wherein,the second housing portion projects radially inward over the bearing seat and / or over a receiving space for a leveling agent.

3. The positive displacement machine according to claim 1,wherein,the second housing portion forms a ring, the inner diameter of which is smaller than the inner diameter of the first housing portion.

4. The positive displacement machine according to claim 1,wherein,the second housing portion forms a sliding surface for the displacement spiral.

5. The positive displacement machine according to claim 1,wherein,at least portions of the first housing portion have a cylindrical inner wall.

6. The positive displacement machine according to claim 1,wherein,the first housing portion has a stepped inner wall or an inner wall with a constant inner diameter.

7. The positive displacement machine according to claim 1,wherein,the second housing portion is connected in a force-transmitting manner with the anti-rotation mechanism.

8. The positive displacement machine according to claim 1,wherein,the anti-rotation mechanism is arranged in the radially inwardly projecting area of the second housing portion.

9. The positive displacement machine according to claim 1,wherein,the anti-rotation mechanism has pins which engage into openings in the displacement spiral for guiding the latter, wherein the pins are introduced into the second housing portion and connected with it.

10. The positive displacement machine according to claim 1,wherein,at least the first housing portion of the bearing plate is connected, in particular screwed, with the housing.

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