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 volute and a stationary volute, there are a plurality of pockets, also called compression chambers, in which a refrigerant is compressed. A certain oil circulation ratio (OCR) is crucial for the scroll compressor to ensure proper sealing between the pockets. If the OCR is too low, internal leakage between successive pockets increases, negatively impacting the efficiency of the scroll compressor. Conversely, if the OCR is too high, it reduces the thermodynamic efficiency of compression because there is too much oil relative to the refrigerant. Therefore, it is necessary to maintain an appropriate OCR level during the operation of the scroll compressor.

[0003] The OCR level can be generated naturally (when oil droplets are carried from a low-pressure side of a scroll compressor by a refrigerant flow) or by any additional equipment (for example, by additional oil injectors). In fixed-speed scroll refrigeration compressors, the amount of naturally generated OCR can be calculated, and if the naturally generated OCR level is insufficient, additional oil can be supplied.

[0004] The OCR level also depends on the operating conditions: at low evaporation temperatures, the refrigerant density is low and fewer oil droplets are carried along. Conversely, at high evaporation temperatures, the refrigerant density is high, resulting in more oil droplets being carried along. However, this effect is secondary and can only affect the OCR level by a maximum of 1 or 2%.

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

[0006] The situation becomes more complex for variable-speed scroll compressors. In this type of scroll compressor, the naturally generated OCR level varies according to the operating speed of the scroll compressor. When the scroll compressor operates at low speed, the refrigerant flow velocity through the scroll compressor is low, and consequently, the number of oil droplets carried by the refrigerant flow is low. Therefore, at low scroll compressor speeds, additional oil distribution is required. On the other hand, when the scroll compressor operates at high speed, the refrigerant flow velocity through the scroll compressor is high, and consequently, the number of oil droplets carried by the refrigerant flow is high.Therefore, at the high speed of the scroll compressor, additional oil distribution is not necessary. Thus, a solution with a variable oil distribution flow rate must be found.

[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 equipment and is therefore complex and expensive.

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

[0009] Finally, document FR2919688A1, which is considered to be the closest art of the technique 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 includes a movable blocking piece, activated by a 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 piece 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 piece is pressed against an orbiting volute by a spring and is therefore in constant sliding contact with the orbiting volute. Thus, this solution is subject to excessive wear. Furthermore, maintaining a good seal between the movable locking piece and the orbiting volute over the lifetime of the scroll compressor is difficult.

[0011] Furthermore, document FR2919688A1 does not provide a reliable solution for ensuring proper lubrication of the contact surface between the orbiting volute and the housing configured to support the axial load from the compressed gas while ensuring orbital movement of the orbiting volute. Since an opening intended to distribute oil to the compression stage is essentially aligned with the axis of rotation 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 to oil injection in the compression stage and, consequently, there will be a lack of oil for this contact surface.

[0012] In addition, the assembly of the movable locking piece at the upper part of the drive shaft requires the 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 disadvantages of prior art solutions and to provide a simple, reliable and inexpensive solution to ensure an appropriate level of OCR during the 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 for supplying the scroll compressor with refrigerant gas to be compressed and a discharge fitting configured to discharge the compressed refrigerant gas,

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

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

[0018] - a drive shaft disposed inside the compressor housing and including a drive unit coupled to the orbiting volute and configured for to drive the orbiting volute into orbital motion, the drive shaft being rotatable around an axis of rotation,

[0019] - a variable-speed electric motor disposed 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 fluidically connected to the oil sump and extending along the entire length of the drive shaft, and oil injection means provided on the orbiting volute and configured to distribute oil from the oil supply channel to the compression volume, and

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

[0022] a mounting body mounted at an upper end face of the drive part, in which the upper end face of the drive part and the mounting body define a first volume in fluidic communication with the oil supply channel of the drive shaft, and the mounting body and the orbiting volute define at least partially a second volume in fluidic 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 so as to be in fluidic communication with each other; and

[0024] a movable oil flow control element 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 which is higher than the first speed, wherein the oil flow control element permits oil flow through the oil passage opening when the oil flow control element is in the first position and restricts oil flow through the oil passage opening when the oil flow control element 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 volute. Consequently, the 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] Furthermore, 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] In addition, the size (diameter) of the oil injection means can be considerably increased to further improve the oil injection flow rate at low speed of a compressor, since the 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 to the drive shaft.

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

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

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

[0032] According to one embodiment of the invention, the oil supply channel opens into the upper end face of the drive part. Advantageously, one 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 fluidic 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 fluidic communication with the oil injection means, is defined by the mounting body, the orbiting volute 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 over 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 from flowing 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 seal 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 control element is configured to be moved from the first position to the second position under the effect of a centrifugal force, that is to say when the centrifugal force acting on the oil flow control element is greater than a predetermined threshold force.

[0044] According to one embodiment of the invention, the oil flow control 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 regulation element has a curved shape.

[0046] According to one embodiment of the invention, the oil flow regulating 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 regulating element. For example, the oil flow regulating 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 consequently rapidly affect the oil flow through the oil passage opening) and slowly move from the intermediate position to the second position as the speed of the variable speed electric motor increases from the intermediate speed to the second speed (and consequently slowly affect the oil flow through the oil passage opening and provide a smooth closure of the oil passage opening).

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

[0048] According to one embodiment of the invention, the oil flow regulating element has a shape that corresponds at least partially 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 hermetically without the need for additional sealing elements.

[0049] According to one embodiment of the invention, the spiral compressor further comprises a support arrangement including a thrust bearing surface on which the orbiting volute 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 includes a thrust bearing lubrication channel formed in the drive shaft and being in fluidic communication with the first volume.

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

[0052] According to one embodiment of the invention, when the oil flow regulating element is in the first position, the oil flow regulating element extends, in a top view, at least partially between the oil passage opening and the upper end of the oil supply channel. Consequently, when the oil flow regulating element is in the first position, the oil flow regulating 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 orifice of the thrust bearing lubrication channel are each located angularly with respect to the axis of rotation of the drive shaft such that, when the oil flow regulating element is in the first In this position, the oil from the oil supply channel is distributed first 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 positioned at an angle relative to the drive shaft's axis of rotation. Therefore, when the oil flow control element is in the first position, the oil exiting the oil supply channel reaches the thrust bearing lubrication channel first before reaching the oil passage opening. This configuration of the scroll compressor ensures a reliable and constant oil supply, particularly to the thrust bearing surface, and prevents oil starvation.

[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 with respect 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 port and the oil passage opening are substantially diametrically opposed with respect to the axis of rotation of the drive shaft.

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

[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 through 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 volute further comprises a cylindrical hub in which the drive part of the drive shaft is at least partially mounted.

[0060] According to one embodiment of the invention, the spiral compressor also includes a hub bearing provided in the cylindrical hub and configured to cooperate with the drive part 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 regulation 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 press-fitted onto the drive part of the drive shaft.

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

[0066] According to one embodiment of the invention, the indexing device comprises a protruding element provided on the drive part and protruding from the upper end face of the drive part, and a receiving hole provided on the mounting body and into which the protruding 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 salient 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 volute and in fluidic communication with the second volume, and at least one injection orifice provided on the orbiting base plate of the orbiting volute and being in fluidic 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, 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 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 guide the upper guided portion of the drive shaft in rotation, and a lower main bearing configured to guide the lower guided portion of the drive shaft in rotation.

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

[0074] The following detailed description of an 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. 1 is a longitudinal cross-sectional view of a spiral compressor according to an embodiment of the invention.

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

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

[0078] Figure 4 is a partial longitudinal cross-sectional view of the scroll compressor of the [Fig.1] taken along a cutting plane offset angularly with respect to that of the [Fig.2].

[0079] Fig. 5 is a perspective top view of an oil flow control device for the scroll compressor of Fig. 1.

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

[0081] Figure 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. 1 provided with the oil flow control device of Fig. 5.

[0083] Description of the preferred embodiment of invention 11

[0084] Fig. 1 represents a longitudinal cross-sectional view of a spiral compressor 2 according to an embodiment of the present invention.

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

[0086] The scroll compressor further includes a base plate 6 fixed 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 by the suction connection 4, and comprises a fixed volute 9 which is fixed relative to the compressor housing 3, and an orbiting volute 11 configured to perform an orbital movement relative to the fixed volute 9 during the operation of the spiral compressor 2. Advantageously, the orbiting volute 11 is supported by and in sliding contact with a thrust bearing surface 12 provided on the support arrangement 7, and the fixed volute 9 and the orbiting volute 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 to 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 volute 11 comprises an orbiting base plate 11.1 having an upper face oriented towards the fixed volute 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 volute 11 also comprises an orbiting spiral winding 11.2 projecting from the upper face of the orbiting base plate 11.1 towards the fixed volute 9. The orbiting spiral winding 11.2 of the orbiting volute 11 meshes with the fixed spiral winding 9.2 of the fixed volute 9 to form a plurality of compression chambers 14 between them. Each of the compression chambers 14 has a variable volume that decreases from the outside to the inside when the orbiting volute 11 is driven into orbit relative to the fixed volute 9.

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

[0091] The drive shaft 15 includes, 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 volute 11 and projecting downwards 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 volute 11 in an orbital motion relative to the fixed volute 9 when the variable speed electric motor 16 is activated.

[0092] The drive shaft 15 also includes 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 includes an upper main bearing 22 provided on the support arrangement 7 and configured to guide the rotation of the upper guided portion 19 of the drive shaft 15, and a lower main bearing 23 configured to guide the rotation of the lower guided portion 21 of the drive shaft 15. The scroll compressor 2 also includes 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 includes 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] In addition, the scroll compressor 2 includes an oil injection system configured to inject oil at least into the compression volume 13.

[0095] The oil injection system includes in particular an oil supply channel 26 fluidly connected to the oil sump 25 and extending along 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 volute 11. The oil supply channel 26 is inclined with respect to the longitudinal axis of the drive shaft 15, and is in particular configured to supply the upper parts of the scroll compressor 2 with oil from the oil sump 25.

[0096] The oil injection system also includes oil injection means provided on the orbiting volute 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 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 fluidic communication with a respective injection channel 27. Advantageously, each injection channel 27 is straight, 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 includes an oil flow control device 29 configured to regulate an oil flow 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 on the upper end face 17.1 of the drive portion 17 and, for example, press-fitted onto the drive portion 17 of the drive shaft 15. In one embodiment shown in the figures, the mounting body 31 comprises a circular base wall 32 extending perpendicularly to the axis of rotation A of the drive shaft 15, and a cylindrical peripheral wall 33 extending from the base wall 32 towards the drive shaft 15. The upper end face 17.1 of the drive portion 17 may, for example, comprise an annular mounting groove into 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 fluidic communication with the oil supply channel 26 of the drive shaft 15, and the mounting body 31 and the orbiting volute 11 define at least partially a second volume 35 in fluidic 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 volute 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 so as to be in fluidic 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 with respect 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 includes 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 that is higher than the first speed. Advantageously, the oil flow control element 37 allows Oil flows through the oil passage opening 36 when the oil flow control element 37 is in the first position, and oil flows through the oil passage opening 36 is prevented when the oil flow control element 37 is in the second position. Specifically, the oil flow control element 37 is configured to hermetically seal the oil passage opening 36 when it is in the second position.

[0103] As shown in [Fig.7], when the oil flow control element 37 is in the first position, the oil flow control 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 control 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 control element 37 can, 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 control element 37 can, for example, be fixed to the peripheral wall 33 of the mounting body 31.

[0105] Advantageously, the oil flow control 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 control element 37 exceeds a predetermined threshold force. Advantageously, the oil flow control element 37 has a shape that corresponds at least partially to that of the peripheral wall 33, at least when the oil flow control element 37 is in the second position. With such a shape of the oil flow control element 37, the oil passage opening 36 can be fluidically sealed hermetically without the need for additional sealing elements when the oil flow control element 37 is in the second position.

[0106] The oil flow control element 37 may comprise a first section 37a, a second section 37b, and a third section 37c which are longitudinally offset from one another and have different elasticities, such that each of the first, second, and third sections 37a to 37c deforms under the effect of a centrifugal force at a different rate / level. For example, the first section 37a has the lowest elasticity, the second section 37b has medium elasticity, and the third section 37c has the highest elasticity. In such a scenario, during the operation of the scroll compressor 2, first the The third section 37c will begin 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 element 37 can be obtained and the control of oil flow through the oil passage opening 36 is further improved.

[0107] As best shown in Figures 3 and 4, the scroll compressor 2 further includes an indexing device configured to define a unique angular position of the mounting body 31 relative to the drive part 17. According to the embodiment shown in the figures, the indexing device includes a projecting element 39 provided on the drive part 17 and projecting from the upper end face 17.1 of the drive part 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 offset laterally with respect to a central axis of the base wall 32, and the projecting element 39 is offset laterally with respect to a central axis B of the drive part 17 and can, for example, be centered on the rotation axis 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 through the oil supply channel 26.

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

[0110] The oil injection system also includes an oil supply passage 43 (see [Fig. 1]) which is at least partially defined by an upper counterweight 44, connected to the drive part 17 and configured to at least partially balance the mass of the orbiting volute 11, and which is configured to be supplied with oil from the oil outlet port 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 some of the oil located inside the first volume 34 can flow towards the internal diameter of the upper counterweight thanks to to a centrifugal load, then be pushed 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 orifice 42.1 of the thrust bearing lubrication channel 42 are angularly offset with respect to the axis of rotation A of the drive shaft 15 and are positioned angularly with respect to the axis of rotation A of the drive shaft 15 such that, when the oil flow regulating element 37 is in the first position, the oil from the oil supply channel 26 is distributed primarily 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 orifice 42.The thrust bearing lubrication channels 42 are located angularly with respect 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, particularly to the thrust bearing surface 12 and prevents a lack of oil for it.

[0113] According to the embodiment shown in the figures, the oil inlet port 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 port 42.1 and the oil passage opening 36 can be substantially diametrically opposite with respect to the axis of rotation A of the drive shaft 15.

[0114] During the operation of the scroll compressor 2, oil is distributed from the oil sump 25 to the first chamber 34 through the oil supply channel 26 in the drive shaft 15. The oil is spread into the first chamber 34 in a circle centered on the axis of rotation 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 oil reaches the first chamber 34), the radius of the oil-free surface circle RI is larger than the radius of the oil-free surface circle R2 at the second speed (high speed) of the variable-speed electric motor 16 (i.e., when a sufficient amount of oil reaches the first chamber 34). This is related to 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 flow of oil through the oil supply channel 26), the oil. It preferentially supplies the surface lubrication channel of the thrust bearing 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 ensures in particular appropriate lubrication of the compression unit 8.

[0116] At the second speed (high speed) of the variable speed electric motor 16, the oil flow control element 37 is moved, under the effect of a 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 exit 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 lubricate at least partially the upper main bearing 22 and / or the hub bearing 24 with 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 include 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 by way of non-limiting examples, but on the contrary encompasses all of its embodiments.

Claims

Demands

1. Scroll compressor (2) comprising: - a compressor housing (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 housing (3) and configured to compress the refrigerant gas supplied by the suction connection (4), the compression unit (8) comprising a fixed volute (9) and an orbiting volute (11) configured to perform an orbital motion relative to the fixed volute (9) during the operation of the scroll compressor (2), the fixed volute (9) and the orbiting volute (11) defining a compression volume (13), - an oil sump (25) disposed inside the compressor housing (3),- a drive shaft (15) disposed inside the compressor housing (3) and comprising a drive portion (17) coupled to the orbiting volute (11) and configured to drive the orbiting volute (11) in an orbital motion, the drive shaft (15) being rotatable about an axis of rotation (A), - a variable-speed electric motor (16) disposed 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 sump (25) and extending along the entire length of the drive shaft (15), and oil injection means provided on the orbiting volute (11) and configured to distribute oil from the channel oil supply (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, the oil flow control device (29), comprising:, • a mounting body (31) mounted at an upper end face (17.1) of the drive part (17), in which the upper end face (17.1) of the drive part (17) and the mounting body (31) define a first volume (34) in fluidic communication with the oil supply channel (26) of the drive shaft (15), and the mounting body (31) and the orbiting volute (11) define at least partially a second volume (35) in fluidic 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 so as to be in fluidic communication with each other;and • an oil flow control element (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, in which the oil flow control element (37) allows oil to flow through the oil passage opening (36) when the oil flow control element (37) is in the first position and limits the oil to flow through the oil passage opening (36) when the oil flow control element (37) is in the second position.

2. Spiral 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) to the drive shaft (15).

3. 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. Scroll compressor (2) according to claim 2 or 3, wherein the peripheral wall (33) and the oil flow control element (37) define between them a variable oil flow channel (38).

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

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

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

8. 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. Scroll compressor (2) according to claim 8, wherein the oil flow regulating element (37) has a curved shape.

10. 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) including a thrust bearing surface (12) on which the orbiting volute (11) is slidably mounted, the oil injection system being configured to lubricate the thrust bearing surface (12) with oil supplied through the oil supply channel (26).

12. Spiral compressor (2) according to claim 11, wherein the oil injection system includes a thrust bearing lubrication channel (42) formed in the drive shaft (15) and being in fluidic 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 orifice (42.1) opening into the end face upper (17.1) of the drive part (17) and being in fluidic 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 with respect to the axis of rotation (A) of the drive shaft (15), such that, when the oil flow regulating element (37) is in the first position, the oil from the oil supply channel (26) is distributed in priority to the thrust bearing lubrication channel (42) rather than to the oil passage opening (36).

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

16. Spiral 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 part (17).

17. Spiral compressor (2) according to claim 16, wherein the indexing device comprises a projecting element (39) provided on the drive part (17) and projecting from the upper end face (17.1) of the drive part (17), and a receiving hole provided on the mounting body (31) and into which the projecting element (39) is received.

18. Spiral 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 volute (11) and in fluidic communication with the second volume (35) and at least one injection orifice (28) provided on the orbiting base plate (11.1) of the orbiting volute (11) and being in fluidic communication with at least one injection channel (27), at least one injection orifice (28) opening into the compression volume (13).

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