Variable speed scroll refrigeration compressor with an oil flow control device

Abstract

A scroll compressor comprising a compressor housing; a compression unit comprising a fixed volute and an orbiting volute (11) defining a compression volume; an oil sump; a drive shaft (15) comprising a drive portion (17) coupled to the orbiting volute (11); a variable-speed electric motor configured to rotate the drive shaft (15); an oil injection system comprising an oil supply channel (26) fluidically connected to the oil sump and extending along the entire length of the drive shaft (15), and oil injection means (27, 28) provided on the orbiting volute (11) and configured to distribute oil from the oil supply channel (26) to the compression volume (13); and an oil flow control device (29) configured to regulate the oil flow from the oil supply channel (26) to the oil injection means (27, 28). Figure 2

Description

Title of the invention: Variable speed scroll refrigeration compressor with an oil flow control device Field of the invention

[0001] The present invention relates to a variable speed scroll refrigeration compressor with a device for controlling an injection of oil into the compression volume. State of the art

[0002] During the operation of a scroll compressor, between an orbiting scroll and a fixed scroll, there are a plurality of pockets, also called compression chambers, in which a refrigerant is compressed. An oil circulation rate (OCR) level is very important for the scroll compressor to ensure a good seal between the pockets. If the OCR is too low, internal leakage between successive pockets increases and an efficiency of the scroll compressor is negatively affected. On the other hand, if the OCR is too high, it causes a decrease in the thermodynamic efficiency of a compression since there is too much oil compared to the refrigerant. Therefore, it is necessary to ensure an appropriate OCR level during the operation of the scroll compressor.

[0003] The OCR level may be generated naturally (when oil droplets are entrained from a low pressure side of a scroll compressor by a refrigerant flow) or by any additional hardware (e.g., by additional oil injectors). In fixed-speed scroll refrigeration compressors, the amount of naturally generated OCR may be calculated, and if the naturally generated OCR level is insufficient, additional oil may be dispensed.

[0004] The OCR level also depends on the operating conditions: at low evaporation temperatures, the refrigerant density is low and fewer oil droplets are entrained. On the contrary, at high evaporation temperatures, the refrigerant density is high, which means that more oil droplets are entrained. However, this effect is secondary and can only affect the OCR level by 1 or 2% at most.

[0005] Document JP2003286976A discloses a scroll compressor with oil distribution holes distributing a lubricating oil to a compression stage of the scroll compressor. The amount of oil distributed can be adjusted by a hole diameter, which corresponds to an optimal lubricating oil supply amount. Such a solution provides a constant oil distribution rate and is always active.

[0006] The situation becomes more complicated for variable speed scroll refrigeration compressors. In this type of scroll compressors, the level of naturally generated OCR varies depending on an operating speed of the scroll compressor. When the scroll compressor operates at a low speed, a speed of a refrigerant flow flowing through the scroll compressor is low and therefore the amount of oil droplets entrained by the refrigerant flow is low. Therefore, at the low speed of the scroll compressor, additional oil distribution is required. On the other hand, when the scroll compressor operates at a high speed, a speed of a refrigerant flow flowing through the scroll compressor is high and therefore the amount of oil droplets entrained by the refrigerant flow is high.Therefore, at the high speed of the scroll compressor, additional oil distribution is not required. Thus, it is necessary to find a solution with a variable oil distribution flow rate.

[0007] Document FR2984425A1 discloses a scroll compressor with an oil injection device comprising an oil pump. Such a solution provides a variable oil distribution flow rate but requires additional hardware and is therefore complex and expensive.

[0008] Document CN201443509U discloses a scroll compressor with a device for controlling an oil distribution with an oil passage. The device is installed in an orbiting scroll. The amount of oil passing through the oil passage is controlled by controlling a closing time of an oil hole. Such a solution is very complex and expensive. In addition, the space in an orbiting scroll is extremely limited. In addition, since the device is located in the orbiting scroll, it is exposed to a sinusoidal centrifugal load since the motion of the orbiting scroll is an orbit, which makes its development difficult.

[0009] Finally, document FR2919688A1, which is considered to be the closest prior art for the present invention, discloses a variable speed scroll refrigeration compressor comprising an oil injection circuit arranged to inject oil into a compression volume, in which the oil injection circuit comprises a movable blocking part, activated by centrifugal force, between a first position releasing the oil injection means and allowing the injection of oil into the compression volume and a second position blocking the oil injection means and preventing the injection of oil into the compression volume, the blocking part being arranged to be moved to its second position when the speed of the scroll compressor exceeds a predetermined value.

[0010] However, the movable locking part is pressed against an orbiting scroll by a spring and is therefore in constant sliding contact with the orbiting scroll. Thus, this solution is exposed to excessive wear. Then, it is difficult to maintain a good seal between the movable locking part and the orbiting scroll during a lifetime of the scroll compressor.

[0011] Furthermore, document FR2919688A1 does not provide a reliable solution to ensure proper lubrication of the contact surface between the orbiting scroll and the housing configured to support the axial load from the compressed gas while providing orbital movement of the orbiting scroll. Since an opening for delivering oil to the compression stage is essentially aligned with the rotational axis of the drive shaft, it is possible that the majority of the oil passing through an oil supply channel provided on the drive shaft will go directly for oil injection into the compression stage and, as a result, there will be a lack of oil for this contact surface.

[0012] Furthermore, assembly of the movable locking piece at the upper portion of the drive shaft requires application of a preload to the spring configured to cooperate with the movable locking piece and is, therefore, at least slightly difficult. Summary of the invention

[0013] An object of the present invention is to overcome the aforementioned drawbacks of prior art solutions and to provide a simple, reliable and inexpensive solution for ensuring an appropriate OCR level during operation of a variable speed scroll compressor.

[0014] According to the present invention, a scroll compressor is provided, comprising:

[0015] - a compressor housing provided with a suction connection configured to supply the scroll compressor with refrigerant gas to be compressed and a discharge connection configured to discharge the compressed refrigerant gas,

[0016] - a compression unit mounted inside the compressor housing and configured to compress the refrigerant gas supplied through the suction connection, the compression unit comprising a fixed scroll and an orbiting scroll configured to perform an orbital movement relative to the fixed scroll during operation of the scroll compressor, the fixed scroll and the orbiting scroll defining a compression volume,

[0017] - an oil sump arranged inside the compressor housing,

[0018] - a drive shaft disposed inside the compressor housing and comprising a drive portion coupled to the orbiting scroll and configured to drive the orbiting scroll in an orbital motion, the drive shaft being rotatable about an axis of rotation,

[0019] - a variable speed electric motor arranged inside the housing of compressor and configured to rotate the drive shaft,

[0020] - an oil injection system configured to inject oil at least into the compression volume, the oil injection system comprising an oil supply channel fluidly connected to the oil sump and extending along the entire length of the drive shaft, and oil injection means provided on the orbiting scroll and configured to distribute oil from the oil supply channel to the compression volume, and

[0021] - an oil flow control device configured to control, i.e. to controlling an oil flow rate from the oil supply channel to the oil injection means, the oil flow rate regulating device, comprising:

[0022] a mounting body mounted at an upper end face of the drive portion, wherein the upper end face of the drive portion and the mounting body define a first volume in fluid communication with the oil supply channel of the drive shaft, and the mounting body and the orbiting scroll at least partially define a second volume in fluid communication with the oil injection means,

[0023] an oil passage opening formed in the mounting body and through which the first volume and the second volume are configured to be in fluid communication with each other; and

[0024] an oil flow control member movable between a first position at a first speed of the variable speed electric motor and a second position at a second speed of the variable speed electric motor that is higher than the first speed, wherein the oil flow control member permits oil flow through the oil passage opening when the oil flow control member is in the first position and restricts oil flow through the oil passage opening when the oil flow control member is in the second position.

[0025] Due to the presence of the first and second volumes, the oil flow control device according to the present invention is not in sliding contact with the orbiting scroll. Therefore, a service life and reliability of the oil flow control device and, thus, of the scroll compressor comprising such an oil flow control device, are improved.

[0026] In addition, the configuration of the oil flow control device according to the present invention ensures easy mounting of the oil flow control device on the drive shaft, and thus simplifies the assembly of the scroll compressor of the present invention.

[0027] Furthermore, the size (diameter) of the oil injection means can be significantly increased to further improve the oil injection rate at low speed of a compressor, since flow through the oil injection means is prevented at high speed of a compressor.

[0028] According to one embodiment of the invention, the mounting body comprises a base wall and a peripheral wall extending from the base wall towards the drive shaft.

[0029] According to one embodiment of the invention, the peripheral wall and the oil flow regulating element define between them a variable oil flow channel, i.e. an oil flow channel having a variable flow cross-section.

[0030] According to one embodiment of the invention, the base wall extends substantially perpendicular to the axis of rotation of the drive shaft.

[0031] According to one embodiment of the invention, the upper end face of the drive portion comprises an annular fixing groove in which the mounting body, and in particular the peripheral wall of the mounting body, is fixed.

[0032] According to one embodiment of the invention, the oil supply channel opens into the upper end face of the drive part. Advantageously, an upper end of the oil supply channel faces the base wall of the mounting body.

[0033] According to one embodiment of the invention, the oil supply channel opens into the first volume.

[0034] According to one embodiment of the invention, the fixed volute comprises a fixed base plate and a fixed spiral winding, and the orbiting volute comprises an orbiting base plate and an orbiting spiral winding, the fixed spiral winding and the orbiting spiral winding forming a plurality of compression chambers. Advantageously, the oil injection means are provided on the orbiting base plate.

[0035] According to one embodiment of the invention, the first volume, which is in fluid communication with the oil supply channel, is defined by the base wall, the peripheral wall and the drive shaft.

[0036] According to one embodiment of the invention, the second volume, which is in fluid communication with the oil injection means, is defined by the mounting body, the orbiting scroll and the drive shaft.

[0037] According to one embodiment of the invention, the base wall of the mounting body is circular.

[0038] According to one embodiment of the invention, the peripheral wall of the mounting body has a cylindrical shape.

[0039] According to one embodiment of the invention, the oil passage opening is formed in the peripheral wall of the mounting body. Such a location of the oil passage opening limits the risk of oil flowing directly from the oil supply channel into the second volume, and thus ensures proper lubrication of a low-speed shaft bearing of the variable-speed electric motor.

[0040] According to one embodiment of the invention, the oil passage opening extends circumferentially on the peripheral wall of the mounting body.

[0041] According to one embodiment of the invention, the oil passage opening is oblong in a circumferential direction. The oil passage opening may have a rectangular shape.

[0042] According to one embodiment of the invention, the oil flow control element is configured to prevent oil flow through the oil passage opening, when the oil flow control element is in the second position. In particular, the oil flow control element is configured to hermetically close the oil passage opening, when the oil flow control element is in the second position. Such a configuration of the oil flow control element ensures that no oil is injected into the high speed (second speed) compression volume of the scroll compressor and consequently improves efficiency.

[0043] According to one embodiment of the invention, the oil flow regulating element is configured to be moved from the first position to the second position under the effect of a centrifugal force, i.e. when the centrifugal force acting on the oil flow regulating element is greater than a predetermined threshold force.

[0044] According to one embodiment of the invention, the oil flow regulating element is elastically deformable between the first and second positions, and is provided with a first fixed end and a second free end.

[0045] According to one embodiment of the invention, the oil flow regulating element has a curved shape.

[0046] According to one embodiment of the invention, the oil flow control element has at least two separate sections with different elasticities. By means of multiple sections with different elasticities, it is possible to obtain a variable characteristic of the oil flow control element. For example, the oil flow control element can be configured to move rapidly from the first position to an intermediate position when the speed of the variable speed electric motor increases from the first speed to a higher intermediate speed. (and therefore quickly affect the flow of oil through the oil passage opening) and slowly move from the intermediate position to the second position when the speed of the variable speed electric motor increases from the intermediate speed to the second speed (and therefore slowly affect the flow of oil through the oil passage opening and provide smooth closing of the oil passage opening).

[0047] According to one embodiment of the invention, the oil flow regulating element comprises a mass element attached at the second free end.

[0048] According to one embodiment of the invention, the oil flow regulating element has a shape which at least partially corresponds to that of the peripheral wall at least when the oil flow regulating element is in the second position. With such a shape of the oil flow regulating element, the oil passage opening can be fluidically sealed without the need for additional sealing elements.

[0049] According to one embodiment of the invention, the scroll compressor further comprises a support arrangement comprising a thrust bearing surface on which the orbiting scroll is slidably mounted, the oil injection system being configured to lubricate the thrust bearing surface with oil supplied by the oil supply channel.

[0050] According to one embodiment of the invention, the oil injection system comprises a thrust bearing lubrication channel formed in the drive shaft and being in fluid communication with the first volume.

[0051] According to one embodiment of the invention, the thrust bearing lubrication channel comprises an oil inlet opening into the upper end face of the drive portion and being in fluid communication with the first volume, and an oil outlet opening into a circumferential outer surface of the drive portion.

[0052] According to one embodiment of the invention, when the oil flow control element is in the first position, the oil flow control element extends, in top view, at least partially between the oil passage opening and the upper end of the oil supply channel. Therefore, when the oil flow control element is in the first position, the oil flow control element forms an oil deflector for at least a portion of the oil exiting the oil supply channel.

[0053] According to one embodiment of the invention, the oil passage opening and the oil inlet port of the thrust bearing lubrication channel are each located angularly relative to the axis of rotation of the drive shaft so that, when the oil flow regulating element is in the first position, the oil from the oil supply channel is distributed with priority to the thrust bearing lubrication channel rather than to the oil passage opening. In other words, the oil passage opening and the oil inlet port of the thrust bearing lubrication channel are each located angularly relative to the axis of rotation of the drive shaft so that, when the oil flow control element is in the first position, the oil leaving the oil supply channel first reaches the thrust bearing lubrication channel before reaching the oil passage opening. Such a configuration of the scroll compressor ensures a reliable, constant oil supply, in particular to the thrust bearing surface and prevents oil starvation therefor.

[0054] According to one embodiment of the invention, the oil passage opening and the oil inlet orifice of the thrust bearing lubrication channel are angularly offset relative to the axis of rotation of the drive shaft.

[0055] According to one embodiment of the invention, the oil inlet orifice is located in a first half-space defined by a reference plane comprising the central axis of the drive part and the axis of rotation of the drive shaft, and the oil passage opening is located in a second half-space defined by the reference plane.

[0056] According to one embodiment of the invention, the oil inlet orifice and the oil passage opening are substantially diametrically opposite relative to the axis of rotation of the drive shaft.

[0057] According to one embodiment of the invention, the scroll compressor further comprises an upper counterweight connected to the drive portion and configured to at least partially balance the mass of the orbiting scroll.

[0058] According to one embodiment of the invention, the oil injection system further comprises an oil supply passage defined at least partially by the upper counterweight and configured to be supplied with oil by the thrust bearing lubrication channel, the oil supply passage being configured to supply the thrust bearing surface with oil.

[0059] According to one embodiment of the invention, the orbiting scroll further comprises a cylindrical hub in which the drive portion of the drive shaft is at least partially mounted.

[0060] According to one embodiment of the invention, the scroll compressor also comprises a hub bearing provided in the cylindrical hub and configured to cooperate with the drive portion of the drive shaft.

[0061] According to one embodiment of the invention, the oil flow regulating element is fixed to the mounting body, and for example to the peripheral wall of the mounting body.

[0062] According to another embodiment of the invention, the oil flow regulating element is fixed to the drive shaft.

[0063] According to one embodiment of the invention, the oil flow regulating element is located in the mounting body, and in particular in the first volume.

[0064] According to one embodiment of the invention, the mounting body is force-fitted onto the drive portion of the drive shaft.

[0065] According to one embodiment of the invention, the scroll compressor further comprises an indexing device configured to define a unique angular position of the mounting body relative to the drive portion.

[0066] According to one embodiment of the invention, the indexing device comprises a projecting element provided on the drive portion and projecting from the upper end face of the drive portion, and a receiving hole provided on the mounting body and in which the projecting element is received.

[0067] According to one embodiment of the invention, the receiving hole is provided on the peripheral wall of the mounting body.

[0068] According to one embodiment of the invention, the projecting element is centered on the axis of rotation of the drive shaft.

[0069] According to one embodiment of the invention, the oil injection means comprise at least one injection channel provided on an orbiting base plate of the orbiting scroll and in fluid communication with the second volume, and at least one injection orifice provided on the orbiting base plate of the orbiting scroll and being in fluid communication with the at least one injection channel, the at least one injection orifice opening into the compression volume.

[0070] According to one embodiment of the invention, the at least one injection orifice opens into an upper face of the orbiting base plate.

[0071] According to one embodiment of the invention, the diameter of the at least one injection orifice is approximately 3 mm.

[0072] According to one embodiment of the invention, the drive shaft comprises an upper guided portion adjacent to the drive portion and a lower guided portion opposite the upper guided portion, and the scroll compressor further comprises an upper main bearing provided on the support arrangement and configured to rotatably guide the upper guided portion of the drive shaft, and a lower main bearing configured to rotatably guide the lower guided portion of the drive shaft.

[0073] According to one embodiment of the invention, the oil injection system is configured to at least partially lubricate the upper main bearing and / or the hub bearing with oil supplied by the oil supply channel. Brief description of the drawings

[0074] The following detailed description of one embodiment of the invention is best understood when read in conjunction with the accompanying drawings, it being understood, however, that the invention is not limited to the specific embodiment disclosed.

[0075] [Fig.l] is a longitudinal sectional view of a scroll compressor according to one embodiment of the invention.

[0076] [Fig.2] is a partial longitudinal sectional view of the scroll compressor of [Fig.l],

[0077] [Fig.3] is an enlarged view of a detail of [Fig.2].

[0078] [Fig.4] is a partial longitudinal sectional view of the scroll compressor of [Fig.l] taken along a section plane angularly offset from that of [Fig.2].

[0079] [Fig.5] is a perspective top view of an oil flow control device of the scroll compressor of [Fig.l].

[0080] [Fig.6] is a bottom perspective view of the oil flow control device of [Fig.5].

[0081] [Fig.7] is a bottom view of the oil flow control device of the [Fig.5],

[0082] [Fig.8] is a cross-sectional view of a drive shaft of the scroll compressor of [Fig.l] provided with the oil flow control device of [Fig.5].

[0083] Description of the preferred embodiment of the invention

[0084] [Fig.l] represents a longitudinal sectional view of a scroll compressor 2 according to an embodiment of the present invention.

[0085] The scroll compressor 2 comprises a compressor casing 3 provided with a suction connection 4 configured to supply the scroll compressor 2 with refrigerant gas to be compressed and a discharge connection 5 configured to discharge the compressed refrigerant gas.

[0086] The scroll compressor further comprises a base plate 6 attached to the compressor housing 3 and providing stable support to the scroll compressor 2.

[0087] The scroll compressor 2 further comprises a support arrangement 7 arranged in the compressor housing 3 and fixed to the compressor housing 3 and a compression unit 8 also arranged in the compressor housing 3 and disposed above the support arrangement 7. The compression unit 8 is configured to compress the refrigerant gas supplied through the suction connection 4, and comprises a fixed scroll 9 which is fixed relative to the compressor housing 3, and an orbiting scroll 11 configured to perform orbital movement relative to the fixed scroll 9 during operation of the scroll compressor 2. Advantageously, the orbiting scroll 11 is supported by and in sliding contact with a thrust bearing surface 12 provided on the support arrangement 7, and the fixed scroll 9 and the orbiting scroll 11 define a compression volume 13.

[0088] In particular, the fixed volute 9 comprises a fixed base plate 9.1 having a lower face oriented towards the orbiting volute 11 and an upper face opposite the lower face of the fixed base plate 9.1. The fixed volute 9 also comprises a fixed spiral winding 9.2 projecting from the lower face of the fixed base plate 9.1 towards the orbiting volute 11.

[0089] The orbiting scroll 11 comprises an orbiting base plate 11.1 having an upper face facing the fixed scroll 9 and a lower face opposite the upper face of the orbiting base plate 11.1 and slidably mounted on the thrust bearing surface 12. The orbiting scroll 11 also comprises an orbiting spiral winding 11.2 projecting from the upper face of the orbiting base plate 11.1 towards the fixed scroll 9. The orbiting spiral winding 11.2 of the orbiting scroll 11 meshes with the fixed spiral winding 9.2 of the fixed scroll 9 to form a plurality of compression chambers 14 therebetween. Each of the compression chambers 14 has a variable volume which decreases from the outside to the inside, as the orbiting scroll 11 is driven into orbit relative to the fixed scroll 9.

[0090] The scroll compressor 2 further comprises a drive shaft 15 arranged in the compressor housing 3 and configured to drive the orbiting scroll 11 in an orbital motion, and a variable speed electric motor 16 arranged inside the compressor housing 3 and coupled to the drive shaft 15. The variable speed electric motor 16 is in particular configured to rotate the drive shaft 15 about an axis of rotation A. According to the embodiment shown in the figures, the variable speed electric motor 16 is arranged below the support arrangement 7.

[0091] The drive shaft 15 comprises, at its upper end, a drive portion 17 which is offset from the longitudinal axis of the drive shaft 15 (and is thus eccentric with respect to the remaining portion of the drive shaft 15), and which is partially mounted in a cylindrical hub 18 provided on the orbiting scroll 11 and projecting downwardly from the orbiting base plate 11.1. The drive portion 17 is configured to cooperate with the cylindrical hub 18 so as to drive the orbiting scroll 11 in an orbital movement relative to the fixed scroll 9 when the variable speed electric motor 16 is activated.

[0092] The drive shaft 15 also comprises an upper guided portion 19 adjacent to the drive portion 17 and a lower guided portion 21 opposite the upper guided portion 19, and the scroll compressor 2 further comprises an upper main bearing 22 provided on the support arrangement 7 and configured to rotatably guide the upper guided portion 19 of the drive shaft 15, and a lower main bearing 23 configured to rotatably guide the lower guided portion 21 of the drive shaft 15. The scroll compressor 2 also comprises a hub bearing 24 provided in the cylindrical hub 18 and configured to cooperate with the drive portion 17 of the drive shaft 15.

[0093] The scroll compressor 2 also comprises an oil sump 25 arranged inside the compressor housing 3 and configured to store oil. The oil sump 25 may for example be at least partially delimited by a lower portion of the compressor housing 3.

[0094] Furthermore, the scroll compressor 2 comprises an oil injection system configured to inject oil at least into the compression volume 13.

[0095] The oil injection system comprises in particular an oil supply channel 26 fluidly connected to the oil sump 25 and extending over the entire length of the drive shaft 15. Advantageously, the oil supply channel 26 has an upper end which opens into an upper end face 17.1 of the drive portion 17 which is oriented towards the orbiting scroll 11. The oil supply channel 26 is inclined relative to the longitudinal axis of the drive shaft 15, and is in particular configured to supply upper parts of the scroll compressor 2 with oil from the oil sump 25.

[0096] The oil injection system also comprises oil injection means provided on the orbiting scroll 11 and in particular on the orbiting base plate 11.1, and configured to distribute oil from the oil supply channel 26 to the compression volume 13.

[0097] According to the embodiment shown in the figures, the oil injection means comprise several injection channels 27 provided on the orbiting base plate 11.1 and each being configured to be fluidically connected to the oil supply channel 26, and several injection orifices 28 provided on the orbiting base plate 11.1 and each being in fluid communication with a respective injection channel 27. Advantageously, each injection channel 27 is rectilinear, and each injection orifice 28 opens into the compression volume 13 and in particular into the upper face of the orbiting base plate 11.1.

[0098] In addition, the scroll compressor 2 comprises an oil flow control device 29 configured to control an oil flow rate from the oil supply channel 26 to the oil injection means.

[0099] As best shown in [Fig. 3], the oil flow control device 29 comprises a mounting body 31 mounted at the upper end face 17.1 of the drive part 17 and, for example, force-fitted onto the drive part 17 of the drive shaft 15. According to one embodiment shown in the figures, the mounting body 31 comprises a base wall 32 which is circular and extends perpendicular to the axis of rotation A of the drive shaft 15, and a peripheral wall 33 having a cylindrical shape and extending from the base wall 32 towards the drive shaft 15. The upper end face 17.1 of the drive part 17 may, for example, comprise an annular fixing groove in which the peripheral wall 33 of the mounting body 31 is fixed. Advantageously, the upper end of the oil supply channel 26 faces the base wall 32 of the mounting body 31.

[0100] The upper end face 17.1 of the drive portion 17 and the mounting body 31 define a first volume 34 in fluid communication with the oil supply channel 26 of the drive shaft 15, and the mounting body 31 and the orbiting scroll 11 at least partially define a second volume 35 in fluid communication with the oil injection means. According to the embodiment shown in the figures, the first volume 34 is defined by the base wall 32, the peripheral wall 33 and the upper end face 17.1 of the drive shaft 15, and the second volume 35 is defined by the mounting body 31, the orbiting scroll 11 and the drive shaft 15. In particular, the oil supply channel 26 opens into the first volume 34, and each injection channel 27 opens into the second volume 35.

[0101] The oil flow control device 29 further comprises an oil passage opening 36 formed in the mounting body 31 and through which the first volume 34 and the second volume 35 are configured to be in fluid communication with each other. According to the embodiment shown in the figures, the oil passage opening 36 is formed in the peripheral wall 33 of the mounting body 31 and is axially offset relative to the upper end face 17.1 of the drive shaft 15. Advantageously, the oil passage opening 36 is oblong in a circumferential direction and has, for example, a rectangular shape.

[0102] The oil flow control device 29 also comprises an oil flow control element 37 movable between a first position (shown for example in [Fig. 6]) at a first speed of the variable speed electric motor 16 and a second position (not shown in the figures) at a second speed of the variable speed electric motor 16 which is higher than the first speed. Advantageously, the oil flow control element 37 allows an oil flow through the oil passage opening 36 when the oil flow regulating member 37 is in the first position and prevents the oil flow through the oil passage opening 36 when the oil flow regulating member 37 is in the second position. In particular, the oil flow regulating member 37 is configured to hermetically close the oil passage opening 36 when the oil flow regulating member 37 is in the second position.

[0103] As shown in [Fig.7], when the oil flow regulating element 37 is in the first position, the oil flow regulating element 37 extends, in top view, at least partially between the oil passage opening 36 and the upper end of the oil supply channel 26.

[0104] According to the embodiment shown in the figures, the oil flow regulating element 37 has a curved shape, and is provided with a first fixed end 37.1 and a second free end 37.2. The oil flow regulating element 37 may for example be located in the first volume 34 and in particular in the mounting body 31, and the first fixed end 37.1 of the oil flow regulating element 37 may for example be fixed to the peripheral wall 33 of the mounting body 31.

[0105] Advantageously, the oil flow regulating element 37 is elastically deformable between the first and second positions, and is configured to be moved from the first position to the second position under the effect of a centrifugal force, i.e. when the centrifugal force acting on the oil flow regulating element 37 is greater than a predetermined threshold force. Advantageously, the oil flow regulating element 37 has a shape which at least partially corresponds to that of the peripheral wall 33 at least when the oil flow regulating element 37 is in the second position. With such a shape of the oil flow regulating element 37, the oil passage opening 36 can be fluidically sealed without the need for additional sealing elements, when the oil flow regulating element 37 is in the second position.

[0106] The oil flow control element 37 may include a first section 37a, a second section 37b, and a third section 37c that are longitudinally offset from each other and have different elasticities, such that each of the first, second, and third sections 37a-37c deforms under centrifugal force at a different rate / level. For example, the first section 37a has the lowest elasticity, the second section 37b has a medium elasticity, and the third section 37c has the highest elasticity. In such a scenario, during operation of the scroll compressor 2, first the third section 37c will start to deform, then the second section 37b and finally the first section 37a. Thus, a variable oil flow channel 38 between the peripheral wall 33 and the oil flow regulating member 37 can be obtained and the oil flow control through the oil passage opening 36 is further improved.

[0107] As best shown in Figures 3 and 4, the scroll compressor 2 further comprises an indexing device configured to define a unique angular position of the mounting body 31 relative to the drive portion 17. According to the embodiment shown in the figures, the indexing device comprises a projecting element 39 provided on the drive portion 17 and projecting from the upper end face 17.1 of the drive portion 17, and a receiving hole 41 provided on the base wall 32 of the mounting body 31 and in which the projecting element 39 is received. Advantageously, the receiving hole 41 is laterally offset from a central axis of the base wall 32, and the projecting element 39 is laterally offset from a central axis B of the drive part 17 and can for example be centered on the axis of rotation A of the drive shaft 15.

[0108] Advantageously, the oil injection system is also configured to lubricate the thrust bearing surface 12 with oil supplied by the oil supply channel 26.

[0109] As best shown in Figures 4 and 8, the oil injection system comprises a thrust bearing lubrication channel 42 which is formed in the drive shaft 15 and which is in fluid communication with the first volume 34. According to an embodiment shown in the figures, the thrust bearing lubrication channel 42 comprises an oil inlet orifice 42.1 opening into the upper end face 17.1 of the drive portion 17 and being in fluid communication with the first volume 34, and an oil outlet orifice 42.2 opening into a circumferential outer surface of the drive portion 17.

[0110] The oil injection system also comprises an oil supply passage 43 (see [Fig.l]) which is at least partially defined by an upper counterweight 44, connected to the drive portion 17 and configured to at least partially balance the mass of the orbiting scroll 11, and which is configured to be supplied with oil from the oil outlet 42.2 of the thrust bearing lubrication channel 42. The oil supply passage 43 is configured in particular to supply the thrust bearing surface 12 with oil from the thrust bearing lubrication channel 42.

[0111] The thrust bearing lubrication channel 42 and the oil supply passage 43 are configured so that a portion of the oil located inside the first volume 34 can flow to the upper counterweight inner diameter through to a centrifugal load, then be forced back at the top of the upper counterweight towards the thrust bearing surface 12.

[0112] Advantageously, the oil passage opening 36 and the oil inlet port 42.1 of the thrust bearing lubrication channel 42 are angularly offset relative to the axis of rotation A of the drive shaft 15 and are located angularly relative to the axis of rotation A of the drive shaft 15 so that, when the oil flow regulating element 37 is in the first position, the oil from the oil supply channel 26 is distributed with priority to the thrust bearing lubrication channel 42 rather than to the oil passage opening 36. In other words, the oil passage opening 36 and the oil inlet port 42.1 of the thrust bearing lubrication channel 42 are located angularly relative to the axis of rotation A of the drive shaft 15 so that, when the oil flow regulating element 37 is in the first position, the oil exiting the oil supply channel 26 first reaches the thrust bearing lubrication channel 42 before reaching the oil passage opening 36. Such a configuration of the scroll compressor 2 ensures a reliable, constant oil supply, in particular to the thrust bearing surface 12 and prevents a lack of oil therefor.

[0113] According to the embodiment shown in the figures, the oil inlet orifice 42.1 is located in a first half-space defined by a reference plane P comprising the central axis B of the drive part 17 and the axis of rotation A of the drive shaft 15, and the oil passage opening 36 is located in a second half-space defined by the reference plane P. For example, the oil inlet orifice 42.1 and the oil passage opening 36 may be substantially diametrically opposite with respect to the axis of rotation A of the drive shaft 15.

[0114] During operation of the scroll compressor 2, oil is distributed from the oil sump 25 to the first volume 34 through the oil supply channel 26 in the drive shaft 15. The oil is spread in the first volume 34 with a circle centered on the rotation axis A of the drive shaft 15. At the first speed (low speed) of the variable speed electric motor 16 (i.e., when a small amount of the oil reaches the first volume 34), the oil-free surface circle radius RI is larger than the oil-free surface circle radius R2 at the second speed (high speed) of the variable speed electric motor 16 (i.e., when a sufficient amount of the oil reaches the first volume 34). This is associated with the oil parabola inside the drive shaft 15.Advantageously, the angular location of the oil passage opening 36 is defined so that when the scroll compressor 2 is operating at first speed (or with a low oil flow rate through the oil supply channel 26), the oil . preferably supplies the thrust bearing surface lubrication channel 42 rather than the oil passage opening 36, and ensures proper lubrication of the shaft bearings. Oil can flow through the oil passage opening 36 only if there is sufficient additional oil exiting the oil supply channel 26.

[0115] The oil passing through the oil passage opening 36 then enters the second volume 35 and is injected into the compression volume 13 via the injection channels 27 and the injection orifices 28, and in particular ensures appropriate lubrication of the compression unit 8.

[0116] At the second speed (high speed) of the variable speed electric motor 16, the oil flow regulating element 37 is moved, under the effect of centrifugal force, into the second position and hermetically closes the oil passage opening 36, so that the oil, entering the first volume 34, can only leave said first volume 34 by flowing into the thrust bearing lubrication channel 42 (without reaching the second volume 35 and thus the injection means).

[0117] Advantageously, the oil injection system is also configured to at least partially lubricate the upper main bearing 22 and / or the hub bearing 24 with the oil supplied by the oil supply channel 26, in particular through radial holes provided on the drive shaft 15 and opening into the oil supply channel 26.

[0118] According to an embodiment of the invention not shown in the figures, the oil flow regulating element 37 may comprise a mass element attached at its second free end 37.2 and / or the oil flow regulating element 37 may be fixed to the drive shaft 15.

[0119] Obviously, the invention is not limited to the embodiments described above as non-limiting examples, but on the contrary encompasses all of its embodiments.

Claims

Claims

1. Scroll compressor (2) comprising: - a compressor casing (3) provided with a suction connection (4) configured to supply the scroll compressor (2) with refrigerant gas to be compressed and a discharge connection (5) configured to discharge the compressed refrigerant gas, - a compression unit (8) mounted inside the compressor casing (3) and configured to compress the refrigerant gas supplied by the suction connection (4), the compression unit (8) comprising a fixed scroll (9) and an orbiting scroll (11) configured to perform an orbital movement relative to the fixed scroll (9) during operation of the scroll compressor (2), the fixed scroll (9) and the orbiting scroll (11) defining a compression volume (13), - an oil sump (25) arranged inside the compressor casing (3),- a drive shaft (15) arranged inside the compressor housing (3) and comprising a drive portion (17) coupled to the orbiting scroll (11) and configured to drive the orbiting scroll (11) in an orbital motion, the drive shaft (15) being rotatable about an axis of rotation (A), - a variable speed electric motor (16) arranged inside the compressor housing (3) and configured to rotate the drive shaft (15), - an oil injection system configured to inject oil at least into the compression volume (13), the oil injection system comprising an oil supply channel (26) fluidically connected to the oil housing (25) and extending over the entire length of the drive shaft (15), and oil injection means provided on the orbiting scroll (11) and configured to distribute oil from the oil supply channel (26) to the compression volume (13),and - an oil flow control device (29) configured to control an oil flow rate from the oil supply channel (26) to the oil injection means, the oil flow control device (29), comprising:, • a mounting body (31) mounted at an upper end face (17.1) of the drive portion (17), wherein the upper end face (17.1) of the drive portion (17) and the mounting body (31) define a first volume (34) in fluid communication with the oil supply channel (26) of the drive shaft (15), and the mounting body (31) and the orbiting scroll (11) at least partially define a second volume (35) in fluid communication with the oil injection means, • an oil passage opening (36) formed in the mounting body (31) and through which the first volume (34) and the second volume (35) are configured to be in fluid communication with each other;and • an oil flow regulating member (37) movable between a first position at a first speed of the variable speed electric motor (16) and a second position at a second speed of the variable speed electric motor (16) which is higher than the first speed, wherein the oil flow regulating member (37) allows oil flow through the oil passage opening (36) when the oil flow regulating member (37) is in the first position and restricts oil flow through the oil passage opening (36) when the oil flow regulating member (37) is in the second position.;

2. A scroll compressor (2) according to claim 1, wherein the mounting body (31) comprises a base wall (32) and a peripheral wall (33) extending from the base wall (31) toward the drive shaft (15).

3. A scroll compressor (2) according to claim 2, wherein the oil passage opening (36) is formed in the peripheral wall (33) of the mounting body (31).

4. A scroll compressor (2) according to claim 2 or 3, wherein the peripheral wall (33) and the oil flow regulating element (37) define therebetween a variable oil flow channel (38).

5. A scroll compressor (2) according to any one of claims 2 to 4, wherein the oil flow regulating element (37) has a shape which at least partially corresponds to that of the peripheral wall (33), at least when the oil flow regulating element (37) is in the second position.

6. A scroll compressor (2) according to any one of claims 1 to 5, wherein the oil flow regulating member (37) is configured to prevent oil flow through the oil passage opening (36), when the oil flow regulating member (37) is in the second position.

7. A scroll compressor (2) according to any one of claims 1 to 6, wherein the oil flow regulating element (37) is configured to be moved from the first position to the second position under the effect of centrifugal force.

8. A scroll compressor (2) according to any one of claims 1 to 7, wherein the oil flow regulating element (37) is elastically deformable between the first and second positions and is provided with a first fixed end (37.1) and a second free end (37.2).

9. A scroll compressor (2) according to claim 8, wherein the oil flow regulating member (37) has a curved shape.

10. A scroll compressor (2) according to claim 8 or 9, wherein the oil flow regulating element (37) has at least two separate sections with different elasticities.

11. A scroll compressor (2) according to any one of claims 1 to 10, further comprising a support arrangement (7) comprising a thrust bearing surface (12) on which the orbiting scroll (11) is slidably mounted, the oil injection system being configured to lubricate the thrust bearing surface (12) with oil supplied from the oil supply channel (26).

12. A scroll compressor (2) according to claim 11, wherein the oil injection system comprises a thrust bearing lubrication channel (42) formed in the drive shaft (15) and being in fluid communication with the first volume (34).

13. A scroll compressor (2) according to claim 12, wherein the thrust bearing lubrication channel (42) comprises an oil inlet port (42.1) opening into the end face upper (17.1) of the drive part (17) and being in fluid communication with the first volume (34), and an oil outlet orifice (42.2) opening into a circumferential external surface of the drive part (17).

14. A scroll compressor (2) according to claim 13, wherein the oil passage opening (36) and the oil inlet port (42.1) of the thrust bearing lubrication channel (42) are each located angularly relative to the rotation axis (A) of the drive shaft (15), so that when the oil flow regulating member (37) is in the first position, oil from the oil supply channel (26) is delivered with priority to the thrust bearing lubrication channel (42) rather than to the oil passage opening (36).

15. A scroll compressor (2) according to any one of claims 1 to 14, wherein the oil flow regulating member (37) is fixed to the mounting body (31).

16. A scroll compressor (2) according to any one of claims 1 to 15, further comprising an indexing device configured to define a unique angular position of the mounting body (31) relative to the drive portion (17).

17. A scroll compressor (2) according to claim 16, wherein the indexing device comprises a protruding member (39) provided on the drive portion (17) and projecting from the upper end face (17.1) of the drive portion (17), and a receiving hole provided on the mounting body (31) and in which the protruding member (39) is received.

18. Scroll compressor (2) according to any one of claims 1 to 17, wherein the oil injection means comprise at least one injection channel (27) provided on an orbiting base plate (11.1) of the orbiting scroll (11) and in fluid communication with the second volume (35) and at least one injection orifice (28) provided on the orbiting base plate (11.1) of the orbiting scroll (11) and being in fluid communication with the at least one injection channel (27), the at least one injection orifice (28) opening into the compression volume (13).

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