Scroll compressor

Abstract

spiral compressor (2) which features: - a hermetic shell (3) comprising a middle shell (4), a top cap (5) and a base plate (6), wherein the base plate (6) comprises: - a mounting base (32) having a plate shape and comprising a central opening (33) and - a central cap (28) arranged within the central opening (33), the central cap (28) having a concave section (29) and a first cylindrical edge section (30) extending upwards and having an outer diameter corresponding to an inner diameter of the central shell (4), - a compression unit (11) designed to compress refrigerant, and - an electric motor (21) configured to drive the compression unit (11) via a drive shaft (19), wherein the mounting base (32) has a second cylindrical edge section (34) extending upwards and surrounding the central openings (33), characterized in that an inner diameter of the second cylindrical edge section (34) corresponds to the inner diameter of the central shell (4) and an outer diameter of the first cylindrical edge section (30).

Description

Field of the invention

[0001] The present invention relates to a scroll compressor according to the preamble of claim 1, in particular a scroll compressor for refrigeration technology. Background of the invention

[0002] Such a scroll compressor is known from CN 101965439 A.

[0003] US 8 152 500 B2 discloses a scroll compressor comprising: - a hermetic housing comprising a center shell, a top cap and a base plate, the base plate comprising: - a plate-shaped mounting base containing a central opening, and - a central cap disposed in the central opening, the central cap comprising a concave portion and a first cylindrical rim portion extending upwards and having an outer diameter substantially corresponding to an inner diameter of the central shell, - a compression unit designed to compress refrigerant, and - an electric motor designed to drive the compression unit via a drive shaft.

[0004] The mounting base of the above-mentioned scroll compressor is fixed to the center cap at a point radially inside the inner diameter of the center shell via an annular weld.

[0005] Such a baseplate configuration leads to vibration and noise problems, especially in common rail systems where at least two scroll compressors are mounted together on a common rail system. In a common rail system in particular, the scroll compressors can experience rocking motion due to the small contact area between the center cap and the mounting base.

[0006] CN 206050550 U shows a tank container frame used in particular for the transport of liquefied natural gas.

[0007] US 2018 / 0021850 A1 shows a scroll compressor having a hermetic housing with a center shell, a top cap and a base plate, wherein the base plate has a plate-shaped mounting base. Summary of the invention

[0008] An object of the present invention is to provide an improved scroll compressor that can overcome the disadvantages encountered in conventional scroll compressors.

[0009] Another object of the present invention is to provide a scroll compressor that greatly reduces vibration and noise problems.

[0010] According to the invention, such a scroll compressor comprises: - a hermetic housing comprising a center shell, a top cap and a base plate, the base plate comprising: - a plate-shaped mounting base containing a central opening, and - a central cap disposed in the central opening, the central cap comprising a concave portion and a first cylindrical rim portion extending upwards and having an outer diameter substantially corresponding to an inner diameter of the central shell, - a compression unit designed to compress refrigerant, and - an electric motor designed to drive the compression unit via a drive shaft, characterized in that the mounting base comprises a second cylindrical edge portion extending upwardly and surrounding the central opening, wherein an inner diameter of the second cylindrical edge portion substantially corresponds to the inner diameter of the central shell and an outer diameter of the first cylindrical edge portion.

[0011] Due to such a configuration of the first and second cylindrical edge portions, the welding of the mounting base and the center cap is easier to control, thus simplifying the manufacturing of the scroll compressor. Furthermore, the resulting base plate allows for more stable mounting of the scroll compressor by increasing the area surrounded by the contact line between the mounting base and the center cap and by enlarging the inner diameter of the center opening, reducing the risk of rocking of the scroll compressor. At the same time, the natural vibration of the entire scroll compressor equipped with the base plate is shifted to a higher level, thereby reducing noise and vibration problems.

[0012] The scroll compressor may also include one or more of the following features, alone or in combination.

[0013] According to one embodiment of the invention, the second cylindrical edge part surrounds at least a lower portion of the first cylindrical edge part.

[0014] According to one embodiment of the invention, the first and second cylindrical edge portions are arranged concentrically.

[0015] According to one embodiment of the invention, the first cylindrical edge part has an axial length that exceeds an axial length of the second cylindrical edge part.

[0016] According to one embodiment of the invention, the middle cap projects upwards from the mounting base.

[0017] According to one embodiment of the invention, the second cylindrical edge part engages with the first cylindrical edge part.

[0018] According to one embodiment of the invention, the second cylindrical edge part is fixed to the middle cap, and in particular to the first cylindrical edge part, for example welded thereto.

[0019] According to one embodiment of the invention, the scroll compressor includes an annular weld joining the first cylindrical edge portion to the second cylindrical edge portion, the diameter of the annular weld substantially corresponding to the inner diameter of the center shell.

[0020] According to one embodiment of the invention, the base plate is designed to be attached to two fastening rails extending substantially parallel to one another.

[0021] According to one embodiment of the invention, the center cap, and for example the concave part of the center cap, is provided with two recesses designed to cooperate with and at least partially accommodate the two mounting rails. Due to such a configuration of the center cap, the overall height of the scroll compressor can be reduced.

[0022] According to one embodiment of the invention, the distance between the two recesses corresponds substantially to the distance between the fastening rails.

[0023] According to one embodiment of the invention, each recess has a shape that is at least partially complementary to the outer shape of the respective fastening rail.

[0024] According to one embodiment of the invention, the mounting base has a generally rectangular shape and, for example, a square shape and includes four lateral outer edges and four downwardly bent flanges each extending from and along a respective one of the four lateral outer edges.

[0025] According to one embodiment of the invention, a first pair of the four downwardly bent flanges is designed to extend substantially parallel to the two fastening rails, and a second pair of the four downwardly bent flanges is designed to extend transversely to the two fastening rails, wherein each downwardly bent flange of the second pair extends only along a central portion of the respective lateral outer edge.

[0026] According to one embodiment of the invention, the scroll compressor further includes an annular weld joint connecting the center shell to the first cylindrical edge portion of the center cap.

[0027] According to one embodiment of the invention, the annular weld joint connects a lower edge of the center shell, the first cylindrical edge portion of the center cap, and an upper edge of the second cylindrical edge portion of the mounting base.

[0028] According to one embodiment of the invention, the center cap includes at least one retainer fixed to an inner surface of the center cap, for example by welding, and configured to support a lower bearing member rotatably supporting the drive shaft, wherein an upper axial end face of the first cylindrical rim portion abuts the at least one retainer. Such a configuration of the center cap allows the vertical positioning of the base plate in the center cap to be achieved prior to welding the base plate to the center cap, thus simplifying the manufacture of the scroll compressor.

[0029] According to one embodiment of the invention, the at least one holder includes a lower axial end face against which the upper axial end face of the first cylindrical edge part abuts.

[0030] According to one embodiment of the invention, the at least one holder is L-shaped.

[0031] According to one embodiment of the invention, the center casing includes a plurality of mounts fixed to the inner surface of the center casing. Advantageously, the mounts are arranged angularly around the drive shaft.

[0032] According to one embodiment of the invention, the mounting base further comprises mounting holes designed to receive mounting elements, for example bolts or screws, for fixing the mounting base to the rails.

[0033] The central shell may have a constant diameter throughout its length, or it may have sections of different diameters.

[0034] According to one embodiment of the invention, the central shell is cylindrical and includes an upper end closed by the upper cap and a lower end closed by the base plate.

[0035] According to one embodiment of the invention, the upper cap is welded to the middle shell.

[0036] According to one embodiment of the invention, the compression unit is arranged within the hermetic housing.

[0037] According to one embodiment of the invention, the scroll compressor includes a lower bearing member and an upper bearing member configured to rotatably support the drive shaft.

[0038] According to one embodiment of the invention, the second cylindrical edge part extends substantially perpendicular to the plane of extension of the fastening base.

[0039] According to one embodiment of the invention, the first and second cylindrical edge portions extend substantially vertically.

[0040] These and other advantages will become apparent upon reading the following description in view of the accompanying drawing of a scroll compressor according to the invention. Short description of the drawings

[0041] The following detailed description of an embodiment of the invention will be better understood when read in conjunction with the accompanying drawings, it being understood, however, that the invention is not limited to the specific embodiment disclosed. Fig. 1 is a longitudinal sectional view of a scroll compressor according to the invention. Fig. 2 and Fig. 3 are longitudinal sectional views of a base plate of the scroll compressor of Fig. 1. Fig. 4 is a plan view of the base plate of the scroll compressor of Fig. 1. Fig. 5 is a partial longitudinal sectional view of the scroll compressor of Fig. 1, which is mounted on two mounting rails. Fig. 6 is a perspective view of the base plate of Fig. 2, which is mounted on two mounting rails. Detailed description of the invention

[0042] Fig. 1 shows a scroll compressor 2 comprising a hermetic housing 3 comprising a center shell 4, a top cap 5 and a base plate 6. As in Fig. As shown in Figure 1, the center shell 4 is cylindrical and includes an upper end closed by the upper cap 5 and a lower end closed by the base plate 6. According to the embodiment shown in the figures, the center shell 4 has a constant diameter over its entire length, and the upper cap 5 is welded to the center shell 4.

[0043] The scroll compressor 2 further includes a suction inlet 7 configured to supply refrigerant to be compressed to the scroll compressor 2, and a discharge outlet 8 configured to discharge compressed refrigerant. For example, the suction inlet 7 may be provided on the center shell 4, and the discharge outlet 4 may be provided on the top cap 5.

[0044] The scroll compressor 2 also includes a support frame 9 disposed within the hermetic housing 3 and fixed to the hermetic housing 3, and a compression unit 11, also disposed within the hermetic housing 3 and positioned above the support frame 9. The compression unit 11 is configured to compress the refrigerant supplied through the suction inlet 7 and includes a fixed scroll 12 fixed relative to the hermetic housing 3 and an orbiting scroll 13 supported by and in sliding contact with a thrust bearing surface 14 provided on the support frame 9.

[0045] The fixed scroll 12 includes a fixed scroll base plate 14 having a bottom surface facing the orbiting scroll 13 and a top surface opposite the bottom surface of the fixed scroll base plate 14. The fixed scroll 12 further includes a fixed spiral winding 15 projecting from the bottom surface of the fixed scroll base plate 14 toward the orbiting scroll 13.

[0046] The orbiting scroll 13 includes an orbiting scroll base plate 16 having an upper surface aligned with the fixed scroll 12 and a lower surface opposite the upper surface of the orbiting scroll base plate 16, which is slidably mounted on the thrust bearing surface 14. The orbiting scroll 13 further includes an orbiting scroll winding 17 projecting from the upper surface of the orbiting base plate 16 toward the fixed scroll 12. The orbiting scroll winding 17 of the orbiting scroll 13 meshes with the fixed scroll winding 15 of the fixed scroll 12 to form a plurality of compression chambers 18 therebetween. Each of the compression chambers 18 has a variable volume that decreases from the outside to the inside as the orbiting scroll 13 is driven to orbit relative to the fixed scroll 12.

[0047] Furthermore, the scroll compressor 2 includes a drive shaft 19 configured to drive the orbiting scroll 13 to an orbital motion, and an electric motor 21, which may be a variable-speed electric motor, coupled to the drive shaft 19 and configured to drive the drive shaft 19 in rotation about a rotation axis A. According to the embodiment shown in the figure, the electric motor 21 is arranged below the support frame 9.

[0048] The drive shaft 19 includes at its upper end portion an eccentric pin 22 which is arranged eccentrically with respect to the rotational axis A of the drive shaft 19 and which is inserted into a connecting sleeve portion 23 provided on the orbiting scroll 13 to cause the orbiting scroll 13 to be driven to an orbital movement with respect to the fixed scroll 12 when the electric motor 21 is operated.

[0049] The scroll compressor 2 further includes an upper bearing member 24 provided on the support frame 9 and configured to engage with an outer peripheral wall surface of the eccentric pin 22, and a lower bearing member 25 configured to engage with an outer peripheral wall surface of a lower end portion 26 of the drive shaft 19. The lower bearing member 24 and the upper bearing member 26 are specifically configured to rotationally support the drive shaft 19.

[0050] In particular, the center shell 4 includes a plurality of brackets 27, which are fixed, for example, by welding, to an inner surface of the center shell 4 and are designed to support the lower bearing member 25. According to the embodiment shown in the figures, the brackets 27 are arranged angularly around the drive shaft, and each bracket 27 is L-shaped.

[0051] As in the Fig. 2 and Fig. 3, the base plate 6 comprises a central cap 28 having a concave portion 29 and a first cylindrical edge portion 30 extending upwardly from the concave portion 29. The first cylindrical edge portion 30 has an outer diameter substantially corresponding to an inner diameter of the central shell 4. As shown in Fig. 1, each holder 24 further includes a lower axial end face 24.1 against which an upper axial end face 31 of the first cylindrical edge part 30 abuts.

[0052] The base plate 6 further comprises a plate-shaped mounting base 32 containing a central opening 33 in which the central cap 28 is arranged. The mounting base 32 comprises a second cylindrical edge portion 34 extending upward and surrounding the central opening 33. The second cylindrical edge portion 34 has an inner diameter that substantially corresponds to the inner diameter of the central shell 4 and an outer diameter of the first cylindrical edge portion 30, and the first and second cylindrical edge portions 30, 34 are arranged concentrically.

[0053] Specifically, the second cylindrical rim portion 34 surrounds a lower portion of the first cylindrical rim portion 30 such that an inner surface of the second cylindrical rim portion 34 faces an outer surface of the first cylindrical rim portion 30. Furthermore, the first cylindrical rim portion 30 has an axial length that exceeds an axial length of the second cylindrical rim portion 34 such that the middle cap 28 protrudes upward from the mounting base 32.

[0054] The second cylindrical edge portion 34 is attached to the first cylindrical edge portion 30. According to the embodiment shown in the figures, the scroll compressor 2 includes an annular weld 35 connecting the first cylindrical edge portion 30 to the second cylindrical edge portion 34. Advantageously, the annular weld 35 is located on an underside of the base plate 6, and the diameter of the annular weld 35 substantially corresponds to the inner diameter of the center shell.

[0055] As in Fig. 4, the mounting base 32 has a generally rectangular shape, and for example a square shape, and includes four lateral outer edges 36.1, 36.2 and four downwardly bent flanges 37.1, 37.2 each extending from and along a respective one of the four lateral outer edges 36.1, 36.2.

[0056] Furthermore, the base plate 6 is advantageously designed to be mounted on two fastening rails 38 extending essentially parallel to one another (see Fig. 5 and Fig. 6). The two downwardly bent flanges 37.1 are designed to extend substantially parallel to the two fastening rails 38, and the two downwardly bent flanges 37.2 are designed to extend transversely and in particular perpendicularly to the two fastening rails 38. Advantageously, each downwardly bent flange 37.2 extends only along a central portion of the respective lateral outer edge 36.2 to define passages for the two fastening rails 38.

[0057] According to the embodiment shown in the figures, the concave part 29 of the central cap 28 is provided with two recesses 39 designed to cooperate with the two mounting rails 38. Advantageously, the distance between the two recesses 39 substantially corresponds to the distance between the mounting rails 38, and each recess 39 has a shape that is at least partially complementary to the external shape of the respective mounting rail 38. This allows the same base plate to be used for mounting a compressor on rails or on flat surfaces.

[0058] The mounting base 32 further comprises mounting holes 41 designed to receive fastening elements, for example bolts or screws, for fixing the mounting base 32 to the rails.

[0059] Furthermore, the scroll compressor 2 contains an annular welding groove 41 (see Fig. 5) connecting the center shell 4 to the first cylindrical edge portion 30 of the center cap 28. Advantageously, the annular weld groove 41 connects a lower edge of the center shell 4, the first cylindrical edge portion 30 of the center cap 28, and an upper edge of the second cylindrical edge portion 34 of the mounting base 32.

Claims

[1] Scroll compressor (2) comprising: - a hermetic shell (3) comprising a middle shell (4), a top cap (5) and a base plate (6), the base plate (6) comprising: - a mounting base (32) having a plate shape and comprising a central opening (33) and - a central cap (28) arranged within the central opening (33), the central cap (28) having a concave portion (29) and a first cylindrical edge portion (30) extending upwards and having an outer diameter corresponding to an inner diameter of the central shell (4), - a compression unit (11) designed to compress refrigerant, and - an electric motor (21) adapted to drive the compression unit (11) via a drive shaft (19), wherein the mounting base (32) has a second cylindrical edge portion (34) extending upwards and surrounding the central openings (33), characterized by that an inner diameter of the second cylindrical edge portion (34) corresponds to the inner diameter of the central shell (4) and an outer diameter of the first cylindrical edge portion (30). [2] Scroll compressor (2) according to claim 1, characterized by that the second cylindrical edge portion (34) surrounds at least a lower part of the first cylindrical edge portion (30). [3] Scroll compressor (2) according to claim 1 or 2, characterized by that the first and second cylindrical edge portions (30, 34) are arranged concentrically. [4] Scroll compressor according to one of claims 1 to 3, characterized bythat the first cylindrical edge portion (30) has an axial length which exceeds an axial length of the second cylindrical edge portion (34). [5] Scroll compressor (2) according to one of claims 1 to 4, characterized by that the center cap (28) protrudes upwards from the mounting base (32). [6] Scroll compressor according to one of claims 1 to 5, characterized by that the second cylindrical edge portion (34) is connected to the center cap (28). [7] Scroll compressor according to one of claims 1 to 6, characterized by that it further comprises an annular weld seam (35) which connects the first cylindrical edge portion (30) to the second cylindrical edge portion (34), wherein a diameter of the annular weld seam (35) corresponds to the inner diameter of the central shell (4). [8] Scroll compressor (2) according to one of claims 1 to 7, characterized bythat the base plate (6) is designed to be mounted on two mounting rails (38) which extend parallel to each other. [9] Scroll compressor according to claim 8, characterized by that the central cap (28) is provided with two recesses (39) which are designed to cooperate with the two mounting rails (38). [10] Scroll compressor according to one of claims 1 to 9, characterized by that the mounting base (32) has a generally rectangular shape and has four lateral outer edges (36.1, 36.2) and four downwardly bent flanges (37.1, 37.2) each extending from and along a respective one of the four lateral outer edges (36.1, 36.2). [11] Scroll compressor according to claims 8 and 10, characterized byin that a first pair of the four downwardly bent flanges (37.1, 37.2) is designed to extend parallel to the two mounting rails (38), and a second pair of the four downwardly bent flanges (37.1, 37.2) is designed to extend transversely to the two mounting rails (38), wherein downwardly bent flanges (37.2) of the second pair extend only along a central part of the respective lateral outer edge (36.1). [12] Scroll compressor according to one of claims 1 to 11, further comprising an annular weld joint (41) connecting the center shell (4) to the first cylindrical edge portion (30) of the center cap (28). [13] Scroll compressor according to claim 12, characterized bythat the annular weld joint (41) connects a lower edge of the central shell (4), the first cylindrical edge portion (30) of the central cap (28) and an upper edge of the second cylindrical edge portion (34) of the mounting base (32). [14] Scroll compressor according to one of claims 1 to 13, characterized by in that the central shell (4) has at least one clamp (27) which is fastened to an inner surface of the central shell (4) and is designed to carry a lower support element (25) which rotatably supports the drive shaft (19), and an upper axial end surface (31) of the first cylindrical edge portion (30) bears against the at least one clamp (27).

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