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(11) | EP 4 417 785 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | CO-ROTATING SCROLL MACHINE |
| (57) A co-rotating scroll machine (1) for displacing and compressing or expanding a fluid,
comprising a drive scroll (5a) comprising at least one drive scroll blade (18a), an
idler scroll (5b) comprising at least one idler scroll blade (18b), a housing (2)
comprising a scroll chamber (32) bounded by a first chamber end wall (11) and a second
chamber end wall (13) and in which the drive scroll and the idler scroll are received,
the drive scroll and the idler scroll being rotatable within the scroll chamber, a
low-pressure port (3), a first high-pressure port (4), a drive shaft (20), an idler
shaft (21), and a coupling mechanism. The drive scroll (5a) is coupled to the drive
shaft (20) and rotatable about an axis (Ad) of the drive shaft (20), the idler scroll
(5b) is coupled to the idler shaft (21) and rotatable about an axis (Ai) of the idler
shaft (21), the axes (Ad, Ai) of the drive shaft (20) and the idler shaft (21) are
parallel and offset, and the coupling mechanism is configured to transmit a force
from the drive scroll (5a) to the idler scroll (5b) to cause the drive scroll (5a)
and the idler scroll (5b) to rotate in the same direction and with the same speed,
a variable volume pump chamber (19) being formed between a pair of contacting said
at least one drive scroll blade (18a) and said at least one idler scroll blade (18b).
The at least one drive scroll blade and at least one idler scroll blade (18a, 18b)
extend in an axial direction from a first axial edge (50a, 50b) to a second axial
edge (51a, 51b), an axial length (L5a) of the drive scroll blade (18a) being equal
to an axial length (L5b) of the idler scroll blade (18b), the first axial edge adjacent
and in sealing proximity to the first chamber end wall (11) and the second axial edge
adjacent and in sealing proximity to the second chamber end wall (13), such that a
pressure in the variable volume pump chamber (19) is exerted on both the first chamber
end wall (11) and the second chamber end wall (13).
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[0002] A scroll machine is a displacement machine for a fluid such as a gas, or a liquid, and is operable as a compressor or an expander. A scroll machine comprises two scrolls each comprising spiral ribs which creates channels. The spiral ribs of the two scrolls are interleaved to form variable spaces for confining, displacing and reducing the volume which compress the fluid between the two scrolls.
[0003] In the operation as a compressor, a volume of the fluid is concomitantly compressed and displaced inside the spiral channels towards the center of the scrolls and subsequently released through a discharge hole near the center of the scrolls. In the operation as an expander, a volume of the fluid is concomitantly expanded and displaced away from the center of the scrolls, performing work on one of the scrolls.
[0004] Three different working principles are known for scroll machines: orbiting, co-orbiting and co-rotating. In orbiting scroll machines, a first scroll is fixed to a housing of the scroll machine and a second scroll eccentrically orbits without rotating, i.e., each point of the second scroll moves along a circle with the same radius and angular position relative to the first scroll. In co-orbiting scroll machines, two scrolls orbit in the same direction with different eccentric radius. In co-rotating scroll machines, a drive scroll and an idler scroll synchronously rotate with respect to the housing about offset parallel axes in the same rotation direction and with the same rotation speed. The idler scroll orbits with respect to the drive scroll in a rotating coordinate system in which the drive scroll is at rest.
[0005] In a co-rotating compressor, the drive scroll is coupled to a drive shaft of a motor. A coupling mechanism transmits a driving force from the drive scroll to the idler scroll to cause a synchronous rotation of the drive scroll and the idler scroll.
[0006] In scroll machines of the prior art, each of the scrolls 5a', 5b' typically comprises a base plate 44a', 44b' on which the spiral ribs 18a', 18b' and spiral radial gaps 19a', 19b' are formed. The pressure of the compressed fluid in the chambers results in an axial force F on the shafts 20', 21' as illustrated in figure 1. The axial force F is transferred to the bearings of the shafts, which is generally undesirable.
[0007] Solutions to the problem of the axial force on the shafts and bearings are known for orbiting scroll compressors, e.g., as disclosed in DE1909604A1, EP0354342A1, US2003194340, and JP2012036876.
[0008] In view of the foregoing, it is an object of the invention to provide a co-rotating scroll machine with a small axial force on the drive and idler shafts.
[0009] It is advantageous to provide a co-rotating scroll machine that is reliable and durable and requires a low maintenance.
[0010] It is advantageous to provide a co-rotating scroll machine that is easy to manufacture and assemble.
[0012] It is advantageous to provide a co-rotating scroll machine that has low vibrations and noise generation.
[0013] Objects of the invention have been achieved by providing a system according to claim 1. Dependent claims set out various advantageous features of embodiments of the invention.
[0014] Disclosed herein is a co-rotating scroll machine for displacing and compressing or expanding a fluid, comprising
- a drive scroll comprising at least one drive scroll blade,
- an idler scroll comprising at least one idler scroll blade,
- a housing comprising a scroll chamber bounded by a first chamber end wall and a second chamber end wall and in which the drive scroll and the idler scroll are received, the drive scroll and the idler scroll being rotatable within the scroll chamber,
- a low-pressure port,
- a first high-pressure port,
- a drive shaft,
- an idler shaft, and
- a coupling mechanism,
[0015] The at least one drive scroll blade and at least one idler scroll blade extend in an axial direction from a first axial edge to a second axial edge, an axial length of the drive scroll blade being equal to an axial length of the idler scroll blade, the first axial edge adjacent and in sealing proximity to the first chamber end wall and the second axial edge adjacent and in sealing proximity to the second chamber end wall, such that a pressure in the variable volume pump chamber is exerted on both the first chamber end wall and the second chamber end wall.
[0016] In an advantageous embodiment, the at least one scroll blades of the drive scroll and the idler scroll have spiral shapes.
[0017] In an advantageous embodiment, the drive scroll comprises a plurality of said drive scroll blades and the idler scroll comprises a plurality of idler scroll blades, said plurality preferably at least four, for instance five.
[0018] In an advantageous embodiment, the drive scroll comprises a central connection axially extending from the first axial edge and connected to the at least one scroll blade of the drive scroll and to the drive shaft, and wherein the idler scroll comprises a central connection axially extending from the second axial edge and connected to the at least one scroll blade of the idler scroll and to the idler shaft.
[0019] In an advantageous embodiment, the coupling mechanism comprises a friction plate arranged between the central connections of the drive scroll and the idler scroll, configured to transfer a torque from the drive scroll to the idler scroll.
[0020] In an advantageous embodiment, the co-rotating scroll machine comprises an elastic element arranged to generate a biasing force in axial direction on the friction plate.
[0021] In an advantageous embodiment, the second chamber end wall comprises at least one mouth for a flow of the fluid between the first high-pressure port and one of the variable volume pump channels.
[0022] In an advantageous embodiment, the at least one mouth is a plurality of mouths arranged on a circle centered on the axis of the idler shaft.
[0023] In an advantageous embodiment, the co-rotating scroll machine comprises at least one check valve configured to block a flow of the fluid from the first high-pressure port into the variable volume pump channels.
[0024] In an advantageous embodiment, the drive scroll comprises a peripheral connection axially extending from the first axial edge and connected to the at least one scroll blade of the drive scroll thereby forming a closed peripheral ring and wherein the idler scroll comprises a peripheral connection axially extending from the second axial edge and connected to the at least one scroll blade of the idler scroll thereby forming a closed peripheral ring.
[0025] In an advantageous embodiment, the coupling mechanism comprises at least one sliding surface on the peripheral connection of the drive scroll cooperating with at least one sliding surface on the peripheral connection of the idler scroll.
[0026] In an advantageous embodiment, the at least one sliding surfaces are arranged to slide with respect to each other in radial directions.
[0027] In an advantageous embodiment, each of the at least one scroll blade of the drive scroll comprises a slit axially extending from the second axial edge and positioned at the at least one sliding surface of the drive scroll 5a and wherein each of the at least one sliding surface of the idler scroll penetrates the slit in a corresponding one of the at least one scroll blade of the drive scroll.
[0028] In an advantageous embodiment, each of the at least one scroll blade of the drive scroll comprises a mouth at a peripheral position for a flow of the fluid into one of the variable volume pump channels.
[0029] In an advantageous embodiment, each of the at least one scroll blade of the idler scroll comprises a slit axially extending from the first axial edge and positioned at the at least one sliding surface of the idler scroll and wherein each of the at least one sliding surface of the drive scroll penetrates the slit in a corresponding one of the at least one scroll blade of the idler scroll.
[0030] In an advantageous embodiment, each of the at least one scroll blade of the idler scroll comprises a mouth at a peripheral position for a flow of the fluid into one of the variable volume pump channels.
[0031] In an advantageous embodiment, the co-rotating scroll machine comprises a second set of a drive scroll, an idler scroll, a drive shaft, an idler shaft, and a coupling mechanism, and a second high-pressure port, wherein the low-pressure port is a common inlet port configured to feed the fluid to the drive and idler scrolls of the first and second sets, and wherein the drive and idler scrolls of the first set are configured to discharge the fluid through the first outlet port and the drive and idler scrolls of the second set are configured to discharge the fluid through the second outlet port.
[0032] In an advantageous embodiment, the drive and idler scrolls of the first and second sets are independently operable.
[0033] Further advantageous features of the invention will be apparent from the following detailed description of embodiments of the invention and the accompanying illustrations.
Brief description of the figures
[0034]
Figure 1 is a schematic view of a pair of drive and idler scrolls of a co-rotating scroll machine of the prior art;
Figure 2 is a perspective view of a co-rotating scroll machine according to an embodiment of the invention;
Figure 3a-c are exploded views of a co-rotating scroll machine according to an embodiment of the invention from different perspectives;
Figure 4a is a cross-sectional view of a co-rotating scroll machine according to an embodiment of the invention illustrating the flow direction (dashed arrows f) of the fluid in compressor operation (drive and idler scrolls not shown);
Figures 4b is a cross-sectional view of a co-rotating scroll machine according to an embodiment of the invention through planes parallel to the axes of the drive and idler scrolls;
Figure 4c is an exploded, cross-sectional view of a part of a co-rotating scroll machine according to an embodiment of the invention including the idler scroll and the idler shaft;
Figure 4d is a cross-sectional view of a co-rotating scroll machine according to an embodiment of the invention zoomed in on the idler shaft assembly;
Figure 4f is a cross-sectional view of a co-rotating scroll machine according to an embodiment of the invention through a plane perpendicular to the axes of the drive and idler scrolls near the first axial edges of the drive and idler scrolls;
Figure 4g is a cross-sectional view of a co-rotating scroll machine according to an embodiment of the invention through a plane perpendicular to the axes of the drive and idler scrolls near the second axial edges of the drive and idler scrolls;
Figure 5 is a perspective view of a drive scroll and an idler scroll of a co-rotating scroll machine according to an embodiment of the invention shown separately (left and middle drawings) and in combination (right drawing);
Figure 6 is a front view (left drawing), a perspective cross-sectional view (middle drawing) and a side cross-sectional view (right drawing) of a drive scroll according to an embodiment of the invention;
Figure 7 is a front view (left drawing), a perspective cross-sectional view (middle drawing) and a side cross-sectional view (right drawing) of an idler scroll according to an embodiment of the invention;
Figure 8 is a front view (top drawings) and a rear view (bottom drawings) of a pair of drive and idler scrolls of a co-rotating scroll machine according to an embodiment of the invention.
In the left drawings, the drive and idler scrolls are concentrically aligned to illustrate their symmetry. In the right drawings, the drive and idler scrolls are eccentrically aligned as required inside the co-rotating scroll machine;
Figure 9 is a front view of a pair of drive and idler scrolls of a co-rotating scroll machine according to an embodiment of the invention at six different rotation angles;
Figure 10 is a schematic view of a check valve of a co-rotating scroll machine according to an embodiment of the invention (top drawings) in a closed state (left drawings) and in an open state (right drawings). The check valve is separately shown in the bottom drawings.
[0035] Referring to the figures, a co-rotating scroll machine according to embodiments of the invention comprises a housing 2, a low-pressure port 3, a high-pressure port 4, a drive scroll 5a, an idler scroll 5b, a drive shaft 20, an idler shaft 21, and a coupling mechanism. The housing 2 comprises a scroll chamber 32 in which the drive scroll 5a and the idler scroll 5b are received.
[0036] The drive scroll 5a is coupled to the drive shaft 20 and rotatable about an axis Ad of the drive shaft 20. The drive scroll 5a may be coupled to the drive shaft 20 by a coupling element 26a on the drive scroll 5a and a coupling element 26c on the drive shaft 20. In the illustrated embodiment, the drive shaft 20 has a notch 26c and is inserted into a center hole 25a of the drive scroll 5a with a protrusion 26a in the center hole 25a fitting into the notch 26c.
[0037] The idler scroll 5b is coupled to the idler shaft 21 and rotatable about an axis Ai of the idler shaft 21. The idler scroll 5b may be coupled to the idler shaft 21 by a coupling element 26b on the idler scroll 5b and a coupling element 26d on the idler shaft 21. In the illustrated embodiment, the idler shaft 21 is inserted into a center hole 25b of the idler scroll 5b and fixed to the idler scroll 5b by a screw 26b and a corresponding thread 26d.
[0038] The drive shaft as well as the motor shaft may be mounted with one or more bearings 34, such as roller bearings or ball bearings.
[0039] The axes Ad, Ai of the drive shaft 20 and the idler shaft 21 are parallel and offset. The coupling mechanism is configured to transmit a force from the drive scroll 5a to the idler scroll 5b to cause the drive scroll 5a and the idler scroll 5b to rotate in the same direction and with the same speed.
[0040] The housing 2 scroll chamber 32 in which the drive scroll 5a and the idler scroll 5b are received comprises a first chamber end wall 11 extending orthogonally to the drive shaft axis and a second chamber end wall 13 extending orthogonally to the drive shaft axis.
[0041] Each of the drive scroll 5a and the idler scroll 5b comprises at least one scroll blade 18a, 18b extending in axial direction from a first axial edge 50a, 50b to a second axial edge 51a, 51b, the first axial edge adjacent the first chamber end wall 11 and the second axial edge adjacent the second chamber end wall 13 . An axial length L5a of the drive scroll 5a is equal to an axial length L5b of the idler scroll 5b. An axial length L12 of the scroll chamber 32 is slightly larger than the axial lengths L5a, L5b of the drive and idler scrolls 5a, 5b to allow a rotation of the drive and idler scrolls 5a, 5b with respect to the housing 2. The first and second axial edges 50a, 50b, 51a, 51b, are in contact with or in very close proximity to the respective first and second chamber end walls 11, 13 to substantially form a seal therebetween such that the flow of fluids across the edges of the scroll blades due to differences in pressure on opposite sides of the scroll blades is restricted. Each scroll blade 18a, 18b may advantageously comprise a tip seal (not shown in the figures, but as per se well known in the art) at one or both of the first and second axial edges 50a, 50b, 51a, 51b to improve the sealing between the scroll blade edges and the chamber end walls.
[0042] The blades 18a, 18b of the drive scroll 5a and the idler scroll 5b are shaped such that radial gaps 19a, 19b are formed radially inside of the blades that allow the respective blades 18a, 18b of the drive scroll 5a and the idler scroll 5b to interleave and form variable volume pump channels 19 between pairs of interleaving blades 18a, 18b, as per se known in co-rotating scroll pumps.
[0043] During rotation of the drive scroll 5a and the idler scroll 5b, each variable volume pump channel may be configured to either compress fluid in the variable volume pump channels, and thus effect a fluid pumping operation, or to function as an expander receiving pressurized fluid driving the scrolls which may be connected to a generator or other device requiring power.
[0044] The scroll machine may be used as a pump to transfer a fluid, or to compress a fluid (on the outlet side), or to create a vacuum (on the inlet side), or to both create a vacuum on one side and compress a fluid on the other side.
[0045] In the illustrated embodiment, the drive and idler scrolls 5a, 5b each have five scroll blades 18a, 18b. However, the drive and idler scrolls 5a, 5b may each have more or fewer than five scroll blades, for instance two, three, four, six, seven or more scroll blades each.
[0046] The scroll blades 18a, 18b of the drive and idler scrolls 5a, 5b preferably have spiral shapes, in particular shapes of Archimedean spirals as shown in the figures. Alternatively, the shapes of the at least one scroll blades 18a, 18b of the drive and idler scrolls 5a, 5b may be involutes or hybrid curves.
[0047] Due to the offset of the axes Ad, Ai of the drive shaft 20, a variable volume pump channel 19 is formed between a contacting pair of scroll blades 18a, 18b, one scroll blade 18a from the drive scroll and one scroll blade18b from the idler scroll, and the first and second chamber end walls 11, 13. The shape of the variable volume pump channel 19 varies with the rotation angle as illustrated in figure 9. There are as many contacting pair of scroll blades 18a, 18b, and associated variable volume pump channels 19, as there are scroll or idler blades.
[0048] The co-rotating scroll machine is configured to be operable exclusively as a compressor, exclusively as an expander, or switchable between compressor and expander operation. The co-rotating scroll machine further comprises a motor for compressor operation, in particular an electric motor 6. The co-rotating scroll machine may further comprise an electric generator for expander operation.
[0049] The housing 2 may comprise multiple sections, which are preferably aligned using alignment elements 16. The housing may comprise a scroll housing section 12 comprising the scroll chamber 32. The first and second chamber end walls 11, 13 may be formed as separate plates. The housing 2 may further comprise a motor housing section 9, in which the motor 6 is located and a connecting housing section 10 between the motor housing section 9 and the first chamber end wall 11. The housing 2 may further comprise an idler shaft housing section 14, in which the idler shaft 21 is mounted. The idler shaft housing section 14 may comprise a cover 15 for covering an idler shaft assembly 17. In the illustrated embodiment, the idler shaft assembly 17 comprises the idler shaft 21 and the bearings 34, first, second and third tubes 36a, 36b, 36c and a conical spring washer 37 for mounting the idler shaft 21 in the idler shaft housing section 14.
[0050] The drive scroll 5a comprises a central connection 24a axially extending from the first axial edge 50a over an axial length L24a and connected to the at least one scroll blade 18a of the drive scroll 5a and to the drive shaft 20. In the illustrated embodiment, the five scroll blades 18a of the drive scroll 5a are connected to the central connection 24a of the drive scroll 5a over the axial length L24a and the center hole 25a of the drive scroll 5a is formed in the central connection 24a of the drive scroll 5a.
[0051] The idler scroll 5b comprises a central connection 24b axially extending from the second axial edge 51b over an axial length L24b and connected to the at least one scroll blade 18b of the idler scroll 5b and to the idler shaft 21. In the illustrated embodiment, the five scroll blades 18b of the idler scroll 5b are connected to the central connection 24b of the idler scroll 5b over the axial length L24b and the center hole 25b of the idler scroll 5b is formed in the central connection 24b of the idler scroll 5b.
[0052] The drive scroll 5a comprises a peripheral connection 27a axially extending from the first axial edge 50a over the axial length L5a and connected to the at least one scroll blade 18a of the drive scroll 5a thereby forming a closed peripheral ring. The idler scroll 5b comprises a peripheral connection 27b axially extending from the second axial edge 51b over the axial length L27b and connected to the at least one scroll blade 18b of the idler scroll 5b thereby forming a closed peripheral ring.
[0053] In the illustrated embodiment, the coupling mechanism comprises sliding surfaces 28a on the peripheral connection 27a of the drive scroll 5a cooperating with sliding surfaces 28b on the peripheral connection 27b of the idler scroll 5b. The sliding surfaces 28a, 28b are oriented for sliding movements in radial directions. The sliding surfaces 28a of the drive scroll 5a are configured to transfer a force to the sliding surfaces 28b of the idler scroll 5b in tangential directions and thus to transfer a torque from the drive scroll 5a to the idler scroll 5b.
[0054] In an advantageous embodiment, the coupling mechanism further comprises a friction plate 30 arranged between the central connections 24a, 24b of the drive scroll 5a and the idler scroll 5b, configured to transfer a torque from the drive scroll 5a to the idler scroll 5b. Advantageously, the co-rotating scroll machine comprises an elastic element arranged to generate a biasing force in axial direction on the friction plate 30.
[0055] The first, second and third tubes 36a, 36b, 36c are spacers between the two bearings 34 and between one of the bearings 34 and the idler scroll 5b, respectively. The first tube 36a connects the inner rotatable parts of the two bearings 34. The second tube 36b connects the outer fixed parts of the two bearings 34. The third tube 36c connects the inner rotatable part of one of the two bearings 34 with the idler scroll 5b. The conical spring washer 37 exerts a force on the fixed part of one of the bearings 34 in axial direction. This force is transferred to the idler shaft 21 and the idler scroll 5b via the bearings 34 of the idler shaft 21 and the first, second and third tubes 36a, 36b, 36c. Thus, the conical spring washer 37 acts as an elastic element arranged to generate a biasing force in axial direction on the friction plate 30. The biasing force is a normal force generating friction between the friction plate 30 and the elements in contact with the friction plate 30, namely, the drive shaft 20, the screw 26b, and parts of the central connections 24a, 24b.
[0056] According to the illustrated embodiment, each of the at least one scroll blade 18a of the drive scroll 5a comprises a slit 29a axially extending from the second axial edge 51a over an axial length L29a and positioned at the at least one sliding surface 28a of the drive scroll 5a, wherein each of the at least one sliding surface 28b of the idler scroll 5b penetrates the slit 29a in a corresponding one of the at least one scroll blade 18a of the drive scroll 5a.
[0057] According to the illustrated embodiment, each of the at least one scroll blade 18a of the drive scroll 5a comprises a mouth 23 at a peripheral position for a flow of the fluid into one of the variable volume pump channels 19. The mouths are not shown in figure 6 for simplicity, i.e., to better highlight other geometrical features of the drive scroll 5a.
[0058] In a variant, the geometry of the drive scroll 5a and the idler scroll 5b is swapped (not illustrated in the figures), i.e., the slits and mouths are formed in the idler scroll.
[0059] The second chamber end wall 13 of the housing 2 comprises at least one mouth 22 for a flow of the fluid between the first high-pressure port 4 and one of the variable volume pump channels 19. The at least one mouth 22 is connected with the first high-pressure port 4 via at least one channel 38. The at least one mouth 22 opens and closes as a function of the rotation angle.
[0060] In an advantageous embodiment (not shown in the figures), the at least one mouth 22 is a plurality of mouths arranged on a circle centered on the axis Ai of the idler shaft 21. For example, the number of mouths corresponds to the number of the at least one scroll blades 18a, 18b of the drive scroll 5a or the idler scroll 5b.
[0061] The co-rotating scroll machine may comprise at least one check valve 40 configured to block a flow of the fluid from the first high-pressure port 4 into the variable volume pump channels 19 for compressor operation. The at least one check valve 40 may each comprise a rigid element 41 and a flexible element 42.
[0062] The housing 2 may comprise a cooling system, in particular for cooling the motor. The cooling system has an inlet 7 and an outlet 8 and may be integrated in the motor housing section 9.
[0063] In an embodiment of the invention (not illustrated in the figures), the co-rotating scroll machine 1 comprises a single set of a drive scroll 5a, an idler scroll 5b, a drive shaft 20, an idler shaft 21, and a coupling mechanism.
[0064] In the illustrated embodiment, the co-rotating scroll machine 1 comprises two sets of a drive scroll 5a, an idler scroll 5b, a drive shaft 20, an idler shaft 21, and a coupling mechanism. The co-rotating scroll machine 1 further comprises two high-pressure ports 4, wherein the low-pressure port 3 is a common inlet port 3 configured to feed the fluid to the drive and idler scrolls 5a, 5b of the first and second sets. The drive and idler scrolls 5a, 5b of the first set are configured to discharge the fluid through the first outlet port 4 and the drive and idler scrolls 5a, 5b of the second set are configured to discharge the fluid through the second outlet port 4. The drive and idler scrolls 5a, 5b of the first and second sets are preferably independently operable.
[0065] One example of use of the illustrated co-rotating scroll machine 1 embodiment is for gas separation.
List of references
[0066]
Co-rotating scroll machine 1
Housing 2
Low-pressure port 3
High-pressure port 4
Channel 38
Scroll housing section 12 (axial length L12)
Scroll chamber 32
Mouth 33
Chamber end walls 11, 13
Mouth 22
Motor housing section 9
Cooling system
Inlet 7
Outlet 8
Idler shaft housing section 14
Connecting housing section 10
Cover 15
Alignment elements 16
Motor 6
Drive shaft 20
Axis Ad
Coupling element 26c
Bearings 35
Idler shaft assembly 17
Idler shaft 21
Axis Ai
Coupling element 26d
Bearings 34
Tubes 36
Elastic element 37
Drive scroll 5a (axial length L5a)
Axial edges 50a, 51a
Scroll blade 18a
Radial gap 19a
Mouth 23
Central connection 24a (axial length L24a)
Center hole 25a
Motor shaft coupling element 26a
Peripheral connection 27a Coupling mechanism
Sliding surface 28a
Slit 29a (axial length L29a)
Friction plate 30
Idler scroll 5b (axial length L5b)
Axial edges 50b, 51b
Scroll blade 18b
Radial gap 19b
Central connection 24b (axial length L24b)
Center hole 25b
Countersink 31
Idler shaft coupling element 26b
Peripheral connection 27b (axial length L27b) Coupling mechanism
Sliding surface 28b
Check valve 40 (optional for compressor operation)
Rigid element 41
Flexible element 42
f: flow direction of fluid in compressor operation
- a drive scroll (5a) comprising at least one drive scroll blade (18a),
- an idler scroll (5b) comprising at least one idler scroll blade (18b),
- a housing (2) comprising a scroll chamber (32) bounded by a first chamber end wall (11) and a second chamber end wall (13) and in which the drive scroll and the idler scroll are received, the drive scroll and the idler scroll being rotatable within the scroll chamber,
- a low-pressure port (3),
- a first high-pressure port (4),
- a drive shaft (20),
- an idler shaft (21), and
- a coupling mechanism,
wherein the drive scroll (5a) is coupled to the drive shaft (20) and rotatable about an axis (Ad) of the drive shaft (20), the idler scroll (5b) is coupled to the idler shaft (21) and rotatable about an axis (Ai) of the idler shaft (21), the axes (Ad, Ai) of the drive shaft (20) and the idler shaft (21) are parallel and offset, and wherein the coupling mechanism is configured to transmit a force from the drive scroll (5a) to the idler scroll (5b) to cause the drive scroll (5a) and the idler scroll (5b) to rotate in the same direction and with the same speed, a variable volume pump chamber (19) being formed between a pair of contacting said at least one drive scroll blade (18a) and said at least one idler scroll blade (18b),
characterized in that the at least one drive scroll blade and at least one idler scroll blade (18a, 18b) extend in an axial direction from a first axial edge (50a, 50b) to a second axial edge (51a, 51b), an axial length (L5a) of the drive scroll blade (18a) being equal to an axial length (L5b) of the idler scroll blade (18b), the first axial edge adjacent and in sealing proximity to the first chamber end wall (11) and the second axial edge adjacent and in sealing proximity to the second chamber end wall (13), such that a pressure in the variable volume pump chamber (19) is exerted on both the first chamber end wall (11) and the second chamber end wall (13).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description